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Rapid monsoon changes since the last deglaciation remain poorly constrained due to the scarcity of geological archives. Here we present a high-resolution scanning X-ray fluorescence (XRF) analysis of a 13.5 m terrace succession on the western Chinese Loess Plateau (CLP) to infer rapid monsoon changes since the last deglaciation. Our results indicate that Rb/Sr and Zr/Rb are sensitive indicators of chemical weathering and wind sorting, respectively, which are further linked to the strength of the East Asian summer monsoon (EASM) and the East Asian winter monsoon (EAWM). During the last deglaciation, two cold intervals of the Heinrich event 1 and Younger Dryas were characterized by intensified winter monsoon and weakened summer monsoon. The EAWM gradually weakened at the beginning of the Holocene, while the EASM remained steady till 9.9 ka and then grew stronger. Both the EASM and EAWM intensities were relatively weak during the Middle Holocene, indicating a mid-Holocene climatic optimum. Rb/Sr and Zr/Rb exhibit an antiphase relationship between the summer and winter monsoon changes on a centennial timescale during 16–1 ka. Comparison of these monsoon changes with solar activity and North Atlantic cooling events reveals that both factors can lead to abrupt changes on a centennial timescale in the Early Holocene. During the Late Holocene, North Atlantic cooling became the major forcing of centennial monsoon events. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of the environmental conditions during the first half of the 2020 mei-yu season (Y20) and the southwest vortex (SWV), as well as their interaction, on heavy precipitation in southern Taiwan during late May 2020, based on a quantitative approach through ensemble simulations. The control experiment successfully replicates observed heavy precipitation in southern and central Taiwan and reveals a positive spatial correlation between precipitation occurrence probabilities and mean accumulated precipitation, emphasizing continuous rainfall accumulation over intermittent extreme events. Comparative analyses with sensitivity experiments elucidate that the Y20, featuring an extended western North Pacific subtropical high, intensify pressure gradients and southwesterly flow near Taiwan, favoring precipitation in windward regions but hindering it in the east. The SWV creates a moist and vortical environment near Taiwan, amplifying moisture supply and westerly winds, promoting precipitation in southern Taiwan, and enhancing frontal activity. The interaction between the SWV and the Y20, though limited in its impact on providing favorable wind and moisture conditions for precipitation southwest of Taiwan, significantly contributes to precipitation in southern Taiwan. The reason is that although the SWV primarily enhances moisture and the Y20 predominantly boost southwesterly flow, creating favorable conditions for rainfall, substantial precipitation occurs only when both factors converge in a nonlinear interaction. The interaction increases frontal activity over the Taiwan Strait and influences the movement and strength of the SWV, enhancing southwesterly flow and moisture flux in southwestern Taiwan. [ABSTRACT FROM AUTHOR]

Transport pathways of air originating in the upper tropospheric Asian monsoon anticyclone are investigated based on three-dimensional trajectories. The Asian monsoon anticyclone emerges in response to persistent deep convection over India and southeast Asia in northern summer, and this convection is associated with rapid transport from the surface to the upper troposphere, and possibly into the stratosphere. Here, we investigate the fate of air that originates within the upper tropospheric anticyclone from the outflow of deep convection, using trajectories driven by ERA-interim reanalysis data. Calculations include isentropic estimates, plus fully three-dimensional results based on kinematic and diabatic transport calculations. Isentropic calculations show that air parcels are typically confined within the anticyclone for 10-20 days, and spread over the tropical belt within a month of their initialization. However, only few parcels (3 % at 360 K, 8 % at 380 K) reach the extratropical stratosphere by isentropic mixing. When considering vertical transport we find that 31 % (48%) of the trajectories reach the stratosphere within 60 days when using vertical velocities or diabatic heating rates to calculate vertical transport, respectively. In both cases, most parcels that reach the stratosphere are transported upward within the anticyclone and enter the stratosphere in the tropics, typically 10-20 days after their initialization at 360 K. This suggests that trace gases, including pollutants, that are transported into the stratosphere via the Asian monsoon system are in a position to enter the tropical pipe and thus be transported into the deep stratosphere. Sensitivity calculations with respect to the initial altitude of the trajectories showed that air needs to be transported to levels of 360 K or above by deep convection to likely (≥50 %) reach the stratosphere through transport by the large-scale circulation. [ABSTRACT FROM AUTHOR]

The article presents a study which describe the Pliocene Model Intercomparison Project (PlioMIP) using the Hadley Centre Model both in atmosphere-ocean coupled mode and atmosphere-only mode. It states that a greater overall warming relative to the control than the atmosphere-only was predicted by the coupled model. The result of the study shows that a reduction in equatorial precipitation and south Asian monsoon was predicted by the atmospheric-only model.

High temporal resolution rainfall data are among the most demanded resources for water resource engineers. In modern times, this need has only multiplied day by day due to the need for training large parameter-heavy models for the prediction of climatic features, analysis of extreme rainfall, etc. However, the availability of such high temporal resolution data is low, which can cause hindrances in research or development projects in several regions. It is therefore imperative to find newer and better models for the disaggregation of rainfall data from lower to higher temporal resolutions, such as a model that uses deep learning neural networks. The main issue with such a model is the requirement for historical rainfall data at different time scales for training, testing, and validating prior to use in practical scenarios, data that may not always be available for all regions necessary. In this paper, an attempt has been to test the accuracy and applicability of pretrained models for the purpose of disaggregating rainfall in other geographical locations, thus reducing the requirement for historical rainfall data for training and validation purposes. A large data set comprising rainfall data from 68 rain gauge stations across the Indian subcontinent has been used to test models pretrained using rainfall data from seven major stations in India (Bikaner, Chennai, Cherrapunji, Delhi, Kolkata, Mumbai, and Mangalore). The pretrained models are tested in their ability to conserve extreme rainfall characteristics by comparing intensity–duration–frequency (IDF) curves generated from observed and disaggregated rainfall, further which the errors in these IDF curves are used to generate heatmaps for the country using the inverse distance weighted interpolation method. At the end of this paper, a map is provided that covers the entire country of study, detailing that a pretrained model can be used for a certain region based on its accuracy of disaggregation and proximity to the city of pretraining data. [ABSTRACT FROM AUTHOR]

Wave data collected along the west coast of India (off Goa, Ratnagiri and Dwarka) during non-monsoon season have been analysed to study the co-existence of wind seas and swells. Diurnal variation in wind and wave parameters is noticeable along the central west coast of India (off Goa and Ratnagiri), and this is not present along the northwest coast of India (off Dwarka). Swells are predominantly mature (91 %) and old (88 %) during late pre-monsoon and post-monsoon seasons, respectively. Sea Swell Energy Ratio quantifies wind sea, swell and mixed seas prevailing in the regions during non-monsoon season. Intermodal Distance (ID) between the energy peaks is moder ately separated during non-monsoon season, whereas, during the shamal events, energy peaks are very close to each other (ID~ 0). However, pure wind seas (ID~ 1) are found to co-exist with the swells during non-monsoon season. Wind seas are growing, when wind and wind seas are opposite to swell direction. Wind seas have minimum angular spreads in multimodal state. Under low winds, the interaction between wind sea and swell dominates and thereby the multimodal state reduces to unimodal state. The fetch available for the evolution of the wind sea spectrum has been estimated, and it is found to be less than 150 km. For the fetch limited condition, a non-dimensional empirical relation has been derived relating the significant wind sea height in terms of wind speed and peak wind sea period, and this relation fits for the west coast of India. [ABSTRACT FROM AUTHOR]

Studies based on upwelling indices (sediment records, sea-surface temperature and wind) suggest that upwelling along the western coast of Arabian Sea is strongly affected by the Indian summer monsoon (ISM). In order to examine this relationship directly, we employ the vertical water mass transport produced by the eddy-resolving global ocean simulation STORM driven by meteorological reanalysis over the last 61 years. With its very high spatial resolution (10 km), STORM allows us to identify characteristics of the upwelling system. We analyze the co-variability between upwelling and meteorological and oceanic variables from 1950 to 2010. The analyses reveal high interannual correlations between coastal upwelling and along-shore wind-stress (r = 0.73) as well as with sea-surface temperature (r = -0.83). However, the correlation between the upwelling and the ISM is small and other factors might contribute to the upwelling variability. In addition, no long-term trend is detected in our modeled upwelling time series. [ABSTRACT FROM AUTHOR]

A simultaneous analysis of 13 years of remotely sensed data of land cover, fires, precipitation, and aerosols from the MODIS, TRMM, and MISR satellites and the AERONET network over Southeast Asia is performed, leading to a set of robust relationships be- tween land-use change and fire being found on inter-annual and intra-annual scales over Southeast Asia, reflecting the heavy amounts of anthropogenic influence over land use change and fires in this region of the world. First, we find that fires occur annually, but with a considerable amount of variance in their onset, duration, and intensity from year to year, and from two separate regions within Southeast Asia from each other. This variability is already partially understood from previous works, including the impacts of both inter-annually and intra-annually occurring influences such as the Monsoon and El-Nino events, but yet there are other as of yet unknown influences that also are found to strongly influence the results. Second, we show that a simple regression-model of the land-cover, fire, and precipitation data can be used to recreate a robust representation of the timing and magnitude of measured AOD from multiple measurements sources of this region using either 8-day (better for onset and duration) or monthly based (better for magnitude) measurements, but not daily measurements. We find that the reconstructed AOD matches the timing and intensity from AERONET measurements to within 70 to 90% and the timing and intensity of MISR measurements from to within 50 to 95%. This is a unique finding in this part of the world, since could-covered regions are large, yet the robustness of the model is still capable of holding over many of these regions, where otherwise no fires are observed and hence no emissions source contribution to AOD would otherwise be thought to occur. Third, we determine that while Southeast Asia is a source region of such intense smoke emissions, that it is also impacted by transport of smoke from other regions as well. There are regions in northern Southeast Asia which have two annual AOD peaks, one during the local fire season, and the second smaller peak corresponding to a combination of some local smoke sources as well as transport of aerosols from fires in southern Southeast Asia, and possibly even from anthropogenic sources in South Asia. Conversely, we show that southern Southeast Asia is affected exclusively by its own local fire sources during its own local fire season. Overall, this study highlights the importance of taking into account a simultaneous use of land-use, fire, and precipitation for understanding the impacts of fires on the atmospheric loading and distribution of aerosols in Southeast Asia over both space and time. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a sustainable inventory model with a learning effect for imperfect quality items under different kinds of fuzzy environments like crisp, general fuzzy, cloudy fuzzy, and monsoon fuzzy. We divided the mathematical model into three parts under the learning effect according to the real-time fuzzy components (crisp, cloudy, and monsoon environments) of the demand rate of the items. We minimized the total inventory cost with respect to cycle length in each environment under the proposed assumptions. The non-linear optimization technique is applied for the algorithm and the solution method to find the decision variable. Finally, we compared the total inventory cost under different fuzzy environments and our finding is that the fuzzy monsoon environment is a more effective fuzzy environment than crisp and cloudy fuzzy environments. We have presented a numerical example for the validation of the proposed model and have shown the impact of the inventory input parameters on the cycle length and total inventory fuzzy cost. The managerial insights and future scope of this proposed study have been shown in the sensitivity analysis and conclusion. The limitations, application, future extension and scope, and social implementation have been shown in this research study. [ABSTRACT FROM AUTHOR]

Over‐estimation of summer precipitation over the Tibetan Plateau (TP) is a well‐known and persistent problem in most climate models. This study demonstrates the impact of a Gaussian Probability Density Function cloud fraction scheme on rainfall simulations using the Weather Research and Forecasting model. It is found that this scheme in both 0.1° and 0.05° resolutions significantly reduces the wet bias through both local feedbacks and large‐scale dynamic process. Specifically, increased cloud water/ice content with this scheme reduces surface shortwave radiation, and consequently surface heat fluxes and evapotranspiration. This, in turn, dampens the large‐scale thermal effect of the TP and weakens the exaggerated monsoon circulation and low‐level moisture convergence. It is this large‐scale dynamic process that contributes the most (∼70%) to the wet bias reduction. Although this paper presents a modeling study, it highlights the cloud radiative feedback to the large‐scale dynamics and precipitation over the TP. Plain Language Summary: Despite numerous attempts to correct the overestimation of summer precipitation over the Tibetan Plateau (TP) in current global and regional climate models, the issue persists. This study applies the Gaussian Probability Density Function (GPDF) cloud fraction scheme in the Weather Research and Forecasting model at two different resolutions (0.1° and 0.05°) during a summer over the TP. The results show that the GPDF scheme significantly mitigates the precipitation overestimation, particularly in the high‐resolution modeling. We explored the physical processes, both local and remote, that contribute to this improvement. Specifically, an increase in cloudiness reduces the amount of radiation reaching the land surface. This decrease in surface radiative heating not only reduces local evaporation but also weakens the thermal effect of the TP. The latter is a major driver of the South Asian monsoon that conveys moisture to the TP, and its weakening reduces moisture convergence over the TP. Both the decreases in local evaporation and remote moisture convergence contribute to the alleviation of the precipitation overestimation, and the latter plays a dominant role. These findings provide a unique perspective for reducing the wet bias over the TP, focusing on the surface available energy and associated remote moisture processes. Key Points: The use of the Gaussian Probability Density Function cloud fraction scheme in high resolution greatly reduces wet bias over the Tibetan Plateau (TP) during summerMore cloud water/ice with the scheme lessens TP's thermal effect, causing a weaker South Asian monsoon and moisture convergenceWet bias reduction is mainly governed by the decrease in remote moisture rather than local evapotranspiration [ABSTRACT FROM AUTHOR]

Blackgram (Vigna mungo L.) holds significant importance among grain legumes, particularly in terms of its production and productivity. Over the years, the decline in the cultivation area of this crop has become increasingly evident due to its persistently low yields. Many technologies are being implemented to improve the yield, and nipping is one of them. The main objective of this paper was to standardize the nipping timing and graded levels of nitrogen (N) application on growth and seed yield in blackgram cultivars under irrigated conditions. A study with three blackgram cultivars (cv.), three levels of N, and three intervals of nipping was taken up during the winter and monsoon seasons of 2018 and 2019, respectively. The study revealed that blackgram cv. VBN8 recorded a higher plant height of 49.52 cm, a higher number of branches (4.08), a higher number of pods per plant (47.75), a higher seed yield of 882 kg.ha−1, and a benefit cost ratio (B:C ratio) of 2.49. Among the graded levels of nutrients, applications of 125% N and 100% phosphorus (P) and potassium (K) recorded the highest growth and yield attributes, with a B:C ratio of 2.33. Nipping at 25 days after sowing (DAS) registered a higher number of branches (4.08), more pods per plant (48.14), and a seed yield of 902 kg.ha−1 with a B:C ratio of 2.36. Higher N, P, and K uptake was observed in blackgram VBN8, with an application of 150% recommended N and 100% P and K and nipping at 25 DAS. To conclude, application of 125% recommended N and 100% P and K and nipping at 25 DAS were found to be significant in enhancing the productivity of blackgram and NPK uptake, and resulted in 14% more profit than no nipping treatments. [ABSTRACT FROM AUTHOR]

Net primary production (NPP) is a fundamental property of natural ecosystems. Temporal variation of NPP not only reflects how communities respond to environmental fluctuations, but it also has important implications for regional carbon assessment. Unfortunately, studies based on field measurements to directly address this issue in the extreme environment of alpine grasslands are rare. In this study, we measured aboveground NPP (ANPP) and species richness in 40 sites across the Tibetan alpine grasslands from 2006 to 2009 to investigate the regional pattern of temporal variation in ANPP and to quantify the effects of climate fluctuation and biodiversity on this variation. The results showed that, during the four-year period, the average ANPP varied 1.5-fold, from 83.9 to 125.7 gm-2, with a mean coefficient of variation of temporal variation of 36.6% across the 40 sites. Due to the regionally similar climatic fluctuations caused by South Asian monsoons, aboveground NPP exhibited synchronous temporal variation and consistent spatial patterns over the four-year period. Moreover, rainfall fluctuation had a more profound effect on the ANPP dynamics than temperature variation, which suggests that production in the Tibetan alpine grasslands is primarily driven by precipitation. Therefore, the Tibetan alpine grasslands are mainly constrained by water availability. Finally, we found that species richness negatively correlates with variation in aboveground NPP, which might provide evidence that diversity can stabilize community production in high-altitude grasslands. [ABSTRACT FROM AUTHOR]

The Bay of Bengal has been traditionally known for its low primary productivity and varied reasons were attributed to it. The data analysis from the sediment traps deployed in the northern Bay of Bengal during the 5 yr from 1994 show episodic events of enhanced downward biogenic flux every year which was not related to monsoon-driven seasonal cycle. Satellite-derived sea level anomaly suggests that the episodic increase in the biogenic flux was associated with the presence of cyclonic eddies in the sediment trap location. Cyclonic eddy-induced down ward biogenic flux in the sediment trap location was larger than the amplitude, ~ 40mg m-2 d-1, of the seasonal cycle. The magnitude of the peak episodic fluxes were one-and-half to two-and-half times the annual mean flux, while the anomaly of peak episodic fluxes was at least equal to or greater than the magnitude of the seasonal flux value. Cyclonic eddies responsible for high biogenic flux during 1994 and 1996 were formed in the northern Bay of Bengal during February--March of respective years due to the interaction of northward flowing western boundary current and coastally trapped Kelvin wave. In contrast, cyclonic eddies during 1997 and 1998 were formed from the breaking of westward propagating Rossby waves. The sediment trap data provided the observational evidence that eddy-induced biological productivity is an important mechanism in the Bay of Bengal that contributes significantly to the mid-depth biogenic flux. [ABSTRACT FROM AUTHOR]

This study attempts to determine the impact of industries such as paper mills and ferro-alloy units and mining of Mn ore deposits on soil and river geochemistry in a monsoon-dominated area on the southwest coast of India. Soils, suspended particulate matter (SPM), andbottom sediments from the Kali River are all enriched with Al, Fe, Ni and Co, but strongly depleted in Na, Ca, K, Mg, Rb and Sr due to intense chemical weathering. However, even in river water the concentrations of dissolved alkaline and alkaline earth elements are low. Manganese, in particular, is anomalously high in bottom sediments and suspended particles by factors of 2.3 to 20.76 in relation to average shale and world river SPM. This enrichment is attributable to mining of Mn ore deposits in the riverdrainage area. The concentration of dissolved Pb, Co and Cd in Kali River water is much higher (by factors of 2 to 13) in comparison to the world's major rivers, implying anthropogenic inputs of these metals through localized discharge of sewage and industrial effluents. Assessment of heavy metal pollution determined by the element enrichment factor (EF) and the index of geo-accumulation (Igeo) suggests that most of the hazardous heavy metals studied are within the background level. However, Al, Fe, Co andNi are enriched due to their immobility during chemical weathering and their adsorption subsequently by Al and Fe oxides. These studies show that, although there are major industries in the study area, their impact is not yet visible due to the large input of pristine sediments from the catchment. [ABSTRACT FROM AUTHOR]

Recent studies have drawn attention to a significant weakening trend of the South Asian monsoon circulation and an associated decrease in regional rainfall during the last few decades. While surface temperatures over the region have steadily risen during this period, most of the CMIP (Coupled Model Intercomparison Project) global climate models have dificulties in capturing the observed decrease of monsoon precipitation, thus limiting our understanding of the regional land surface response to monsoonal changes. This problem is investigated by performing two long-term simulation experiments, with and without anthropogenic forcing, using a variable resolution global climate model having high-resolution zooming over the South Asian region. The present results indicate that anthropogenic effects have considerably influenced the recent weakening of the monsoon circulation and decline of precipitation. It is seen that the simulated increase of surface temperature over the Indian region during the post-1950s is accompanied by a significant decrease of monsoon precipitation and soil moisture. Our analysis further reveals that the land surface response to decrease of soil moisture is associated with significant reduction in evapotranspiration over the Indian land region. A future projection, based on the representative concentration pathway 4.5 (RCP4.5) scenario of the Intergovernmental panel on Climate Change (IPCC), using the same high-resolution model indicates the possibility for detecting the summer-time soil drying signal over the Indian region during the 21st century, in response to climate change. While these monsoon hydrological changes have profound socioeconomic implications, the robustness of the high-resolution simulations provides deeper insights and enhances our understanding of the regional land surface response to the changing South Asian monsoon. [ABSTRACT FROM AUTHOR]

Seasonal cycle of biogenic fluxes obtained from sediment trap at two locations 5°24'N, 86°46'E (SBBT) and 3°34'N, 77°46'E (EIOT) within the equatorial Indian Ocean (EIO) were examined to understand the factors that control them. The sediment trap data at SBBT were collected for ten years from November 1987 while that at EIOT was for one year period from January 1996. The characteristic of biogenic flux at SBBT was the strong seasonality with peak flux in August, while lack of seasonality characterized the flux at EIOT. At the SBBT and EIOT, the higher chlorophyll biomass during summer monsoon was supported by wind-mixing, which supplied new nitrogen to the upper ocean. The stronger winds at SBBT compared to EIOT resulted in greater entrainment of nutrients to the euphotic zone, which supported higher chlorophyll biomass. High cell counts of phytoplankton (>5 µm) at SBBT dominated by diatoms suggest the operation of classical food web and high carbon export. On the contrary, one-and-half time higher magnitude of micro-zooplankton biomass dominated by picophytoplankton along with 2-fold lesser meso-zooplankton at EIOT indicated the importance of microbial loop. The substantial decrease in the carbon export at EIOT indicated faster remineralization of photosynthetically produced organic matter. We see a striking similarity between the biological process that operates in the SBBT with that of the equatorial Atlantic and EIOT with that of the equatorial Pacific, though the physical forcing in these three regions, namely EIO, the equatorial Atlantic and the equatorial Pacific, are very different. [ABSTRACT FROM AUTHOR]

Free-drifting sediment net traps were deployed 14 times at depths between 80 and 500 m for 1-3 days each during the late monsoon/intermonsoon transition in the central Arabian Sea. Two locations (19.5 and 15.5° N) were within the permanently oxygen deficient zone, and a third (11° N) had a shallow and thin oxygen minimum. The secondary nitrite maximum, which serves as a tracer of the oxygen deficient zone (ODZ) zone, thinned from ~ 250 m thick at stations 19.5 and 15.5° N to ~ 50 m thick at station 11° N. Overall, organic carbon fluxes ranged from 13.2 g m² yr-1 at 80 m to a minimum of 1.1 g m² yr-1 at 500 m. Fluxes at the more oxygenated 11° N station attenuate faster than within the permanent ODZ. Martin curve attenuation coefficients for 19.5 and 15.5° N are 0.59 and 0.63 and for 11° N it is 0.98. At least six potential mechanisms might explain why sinking particles sinking through the ODZ are more effectively transferred to depth; (M1) oxygen effects, (M2) microbial loop efficiencies and chemoautotrophy, (M3) changes in zooplankton dynamics, (M4) additions of ballast that might sorb and protect organic matter from decay, (M5) inputs of refractory organic matter, and (M6) changes in sinking speeds. These mechanisms are intertwined, and were explored using a combination of mineral (XPS) and organic matter characterizations of the sinking material and ship-board incubation experiments. Evidence was found supporting an oxygen effect and/or changes in the efficiency of the microbial loop including the addition of chemoautotrophic carbon to the sinking flux in the upper 500 m. Less evidence was found for the other potential mechanisms. A simple conceptual model consistent with our and other recent data suggests that the upper ODZ microbial community determines the initial flux attenuation, and that deeper in the water column zooplankton and sinking speed become more important. The exact interplay between the various mechanisms remains to be further evaluated. [ABSTRACT FROM AUTHOR]

As a response to the invitation to a form of global thought, this paper asks: what is the relationship between Indian classical music and everyday seasonal life? Indian classical music has been studied in the social sciences as a tradition belonging to a distinctly South-Asian past (Neuman, 1980; Mukherjee, 2006), in which newness has emerged only as a consequence of techno-auratic reconfigurations (Neuman in Asian Music, 40(2), 100–123, 2009), or as a construct of India's post-colonial modernity (Neuman, 1980; Mukherjee, 2006). This paper departs from this literature to suggest a different route into the study of this form, which grounds it within the aesthetic labors of thinking and feeling, and the ways in which they relate to everyday variations in the earth's tempos. It argues that a raag is not simply a sequence of notes that represents a culturally specific way of being, but an aesthetic relation that expresses and intervenes in seasonal and diurnal rhythms. By studying raag Malhar within the context of drought-prone rural West Bengal, this paper examines the life of Indian classical music outside the institutional frameworks of concert halls and academies of learning, and begins instead to explore the ways in which it forges and animates everyday life. As such, it works towards a conception of the classical that can be located within the ordinary, and asks, in relation to the concepts of raag and season, what it means for the temporal resonances of everyday life to be musically rendered. [ABSTRACT FROM AUTHOR]

Cultural eutrophication of coastal aquatic systems is a major undesired phenomenon of today, which is mainly ascribed to the application of inorganic fertilizers in agriculture. Consequently, dissolved inorganic nitrogen (DIN) is considered the major problem and widely studied. However, human interventions also strongly influence the riverine dissolved organic nitrogen (DON) concentrations and fluxes. Studies of nutrient inputs from tropical river catchments are biased towards DIN, even though they account for only a portion of the total dissolved nitrogen (TDN) pool, whereas the rest is comprised of DON and has been largely ignored. The tropical Pamba River was studied because of its manifold human activities in the catchment and was sampled during the south west monsoon (SWM), north east monsoon (NEM) and the pre monsoon (PM) months during 2010 to 2013. The largest pilgrim center on earth, the Sabarimala temple, located in the upstream forest is a unique feature of the catchment. Fertilizer application, livestock farming and inadequate sewage treatment are the prevailing land use prac15 tices. The goals of this study were to (i) define cause-effect relationships by assessing the effect of various human interventions such as the pilgrims, agriculture and sewage disposal in combination with the seasonal variations in hydrology on the DON concentrations and fluxes and to (ii) quantify the inputs from respective land use segments. The global maximum DON concentration (29 302 μM) was measured for the Pamba River. Pilgrim activities, high population density, agricultural and livestock farming as well as the lack of infrastructure for sanitation facilities were the cause for extremely high DON concentrations and fluxes in the plantation and settlement with mixed tree crop (SMT) segments. A DON yield of 745 kg ha-1 yr-1 was calculated for the Pamba catchment. The total DON inputs from all quantifiable sources amounted to 514 kg ha-1 yr-1 comprising of 69% of the total Pamba DON yield. In the Pamba River, sewage is the major source of DON and the unique Sabarimala pilgrim event accountsfor most of it. Nevertheless, sewage input from the rest of the densely-populated catchment is high, which is a common feature of developing countries that lack adequate sanitation and water technology, i.e. in South and Southeast Asia and tropical Africa. Our study shows that DON makes up a significant portion of anthropogenic nitrogen in rivers, in particular in those regions, which are, however, scarce in respective data. It underscores the need for more quantitative studies from densely-populated tropical river catchments in order to improve global nitrogen budgets and the assessment of the consequences of anthropogenic nitrogen inputs into coastal aquatic systems. [ABSTRACT FROM AUTHOR]

Hydroxy fatty acids (FAs) in fresh snow from Sapporo, one of the heaviest snowfall regions in the world, have been studied to ascertain the airborne bacterial endotoxin concentrations and their biomass. The presence of β-hydroxy FAs (C9-C28), constituents of Gram-negative bacteria (GNB), suggests long-range transport of soil microbes. Likewise, the occurrence of α- and ω-hydroxy FAs (C9-C30 and C9-C28, respectively) in snow reveals their contribution from epicuticular waxes and soil microorganisms. Estimated endotoxin and GNB mass can aid in assessing their possible impacts on the diversity and functioning of aquatic and terrestrial ecosystems, as well as lethal effects on pedestrians through dispersal of microbes. Air mass back trajectories together with hydroxy FAs unveil their sources from Siberia, Russian Far East and North China by the Asian monsoon. This study highlights the role of fresh snow that reduces the human health risk of GNB and endotoxin by scavenging from the air. [ABSTRACT FROM AUTHOR]

To examine seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in oligotrophic tropical waters under the influence of seasonal reversing monsoon, dilution experiments were conducted during the summer 2009 (21 May to 9 June) and winter 2010 (9 to 18 November) in the southern South China Sea (SSCS). The results showed that environmental variables, phytoplankton biomass, phytoplankton growth rate (µ), microzooplankton grazing rate (m), and correlationship (coupling) between the µ and m, but the microzooplankton grazing impact on phytoplankton (m/µ) significantly varied between the two seasons. Higher relative preference index (RPI) for and m on the larger-sized (>3 µm) phytoplankton than pico-phytoplankton (<3 µm), indicating significant size-selective grazing by microzooplankton on the larger-sized phytoplankton, were also observed. The µ and m were significantly correlated with salinity and dissolved inorganic nutrients, which indicated that salient seasonal variations in the phytoplankton growth and microzooplankton grazing in the SSCS were closely related to the environmental variables under the influence of the East Asian monsoon. We propose that intermittent arrivals of the northeast winter monsoon could lead to the low µ and m, and the decoupling between the µ and m in the SSCS, through influencing nutrient supply to the surface water, and inducing surface seawater salinity decrease. The low m/µ (<50% on average) indicates low remineralization of organic matter mediated by microzooplankton and the increased importance of the phytoplankton-mesozooplankton grazing pathway, and thus probably accounts for part of the high vertical biogenic particle fluxes in the prevailing periods of the monsoons in the SSCS. The size-selective grazing suggests that microzooplankton grazing contributes to the pico-phytoplankton dominance in the oligotrophic tropical waters such as that of the SSCS. [ABSTRACT FROM AUTHOR]

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Systematic, routine, and comprehensive evaluation of Earth system models (ESMs) facilitates benchmarking improvement across model generations and identifying the strengths and weaknesses of different model configurations. By gauging the consistency between models and observations, this endeavor is becoming increasingly necessary to objectively synthesize the thousands of simulations contributed to the Coupled Model Intercomparison Project (CMIP) to date. The Program for Climate Model Diagnosis and Intercomparison (PCMDI) Metrics Package (PMP) is an open-source Python software package that provides quick-look objective comparisons of ESMs with one another and with observations. The comparisons include metrics of large- to global-scale climatologies, tropical inter-annual and intra-seasonal variability modes such as the El Niño–Southern Oscillation (ENSO) and Madden–Julian Oscillation (MJO), extratropical modes of variability, regional monsoons, cloud radiative feedbacks, and high-frequency characteristics of simulated precipitation, including its extremes. The PMP comparison results are produced using all model simulations contributed to CMIP6 and earlier CMIP phases. An important objective of the PMP is to document the performance of ESMs participating in the recent phases of CMIP, together with providing version-controlled information for all datasets, software packages, and analysis codes being used in the evaluation process. Among other purposes, this also enables modeling groups to assess performance changes during the ESM development cycle in the context of the error distribution of the multi-model ensemble. Quantitative model evaluation provided by the PMP can assist modelers in their development priorities. In this paper, we provide an overview of the PMP, including its latest capabilities, and discuss its future direction. [ABSTRACT FROM AUTHOR]

The interaction between clouds and radiation is a key process within the climate system, and assessing the impacts of that interaction provides valuable insights into both the present-day climate and future projections. Many modeling experiments have been designed over the years to probe the impact of the cloud radiative effect (CRE) on the climate, including those that seek to disrupt the mean CRE effect and those that only disrupt the covariance of the CRE with the circulation. Seven such experimental designs have been added to the Energy Exascale Earth System Model version 1 (E3SMv1) of the US Department of Energy. These experiments include both the first and second iterations of the Clouds On/Off Klimate Intercomparison Experiment (COOKIE) experimental design, as well as the cloud-locking method. This paper documents the code changes necessary to implement such experiments and also provides detailed instructions for how to run them. Analyses across experiment types provide valuable insights and confirm the findings of prior studies, including the role of cloud radiative heating toward intensifying the monsoon, intensifying rain rates, and poleward expansion of the general circulation owing to cloud feedbacks. [ABSTRACT FROM AUTHOR]

This paper is a reflective discussion of the research method developed by a small research team over a 5-year period as it intra-acted with the south Asian monsoon in three south/southeast Asian cities. It reflects on how the team's practice was transformed from being research on or about the monsoon as a discrete unit of analysis, to research in the monsoon and with its agential materiality. The paper first outlines the theoretical resources from cultural geography, anthropology, feminist theory, posthuman theory, and science and technology studies that the project drew from. After this theoretical section, the paper then discusses the practical implications of the method and the two emergent strands of research ('weather matters' and 'construction matters') that were followed in Chennai, Dhaka, and Yangon. The final section of the paper reflects on the extension of the method into the formatting of a book and an online exhibition. The paper concludes by arguing that what the method offers to cultural, weather-based research in monsoonal and other climes, is a situated, non-formulaic method that recognizes the affordances of the Earth's agency, of matter and of other-than-human lives for generating knowledge of and ways of being in changing weather-worlds. [ABSTRACT FROM AUTHOR]

The freshwater discharge from melting ice sheets in the deglaciation or glaciation is prone to anomalies in ocean-atmosphere transport between different latitudes, which can lead to a series of abrupt millennial-scale climate events, either obvious or not, such as the Younger Dryas (YD) events and YD-like events. Marine Isotope Stage 11c (MIS 11c) serves as one of the best references for the current Holocene, and the studies of possible YD-like events and their triggering mechanisms during Holocene are conducive to the understanding of the occurrence pattern of extreme climate events. In this paper, the results of the study on the J33 δ18O sequence records of stalagmites in Jinfo Cave, Chongqing, are shown: (1) Stalagmites in the Asian monsoon climate zone reveal a millennial-scale weak monsoon event that occurred around 410 ka BP prior to the Glacial Maximum of MIS 11 interglacial period. (2) Both the 410 ka weak monsoon event and the YD event occurred during the gradual strengthening of the monsoon and ascending branch of summer insolation in the Northern Hemisphere prior to the Glacial Maximum of interglacial period. This was also a time when Atlantic Meridional Overturning Circulation (AMOC) disturbance occurred. The duration, internal structure, and pattern of the events were similar, with differences in the change magnitude and ice volume conditions. (3) The weak monsoon event that occurred in 410 ka BP was primarily influenced by the combined effects of insolation and AMOC. This event was characterized by a sustained warming process that accelerated the melting of the Greenland ice sheet, leading to the destabilization of this ice sheet. The continuous flowing of freshwater into the North Atlantic resulted in a short-lived AMOC oscillation. The weakening of the AMOC resulted in a cold anomaly over the North Atlantic. As a result of atmospheric telecorrelation, the weaker AMOC led to a weaker Asian Summer Monsoon (ASM). [ABSTRACT FROM AUTHOR]

Dynamical prediction of monsoon rainfall has been an important topic and a long-standing issue in both research and operational community. This paper provides a comprehensive evaluation of the subseasonal-to-seasonal (S2S) prediction skill of the East Asian summer monsoon (EASM) rainfall using the hindcast record from the Beijing Climate Center Climate System Model, BCC CSM1.1m, during the period 1983–2019. The model exhibits reasonable skills for predicting the EASM rainfall at all lead times with the skill dropping dramatically from the shortest lead time of about 2 weeks (LM0) to 1-month lead (LM1), and then fluctuating remarkably throughout 2-month to 12-month lead times. Over the EASM domain, the rapid decline of the S2S rainfall prediction skill from LM0 to LM1 is mainly caused by the inferior skills over Central China in July and over Northeast China in August. Composite analysis based on hindcast records suggest that these inferior skills are directly tied to the model's difficulties in capturing above-normal precipitation over eastern Central China and Northeast China in the respective months, which are further shown to be associated with anomalous weakening and meridional movement of the Northwestern Pacific subtropical high and the activity of large-scale teleconnection pattern hard to be predicted over northeastern Asia in summer, respectively. These findings inform the intrinsic limits of the S2S predictability of the EASM rainfall by a dynamical model, and strongly suggest that the level of confidence placed upon S2S forecasts should be stratified by large-scale circulation anomalies known to significantly affect the prediction skill, e.g., the subtropical high and high-latitude teleconnection patterns for summer monsoon rainfall prediction in this region. [ABSTRACT FROM AUTHOR]

In this study, 56 groundwater samples were taken from diverse sources in Bangalore Urban district during the pre-monsoon and post-monsoon seasons to measure the uranium concentration and its correlation with different water-quality parameters. The uranium concentration varied from 0.94-98.79 µg/L during the pre-monsoon season and from 1.38-96.52 µg/L during the post-monsoon season. Except for a few readings, all were within the safe limit of 60 µg/L as prescribed by India's Atomic Energy Regulatory Board (AERB), Department of Atomic Energy (DAE). Owing to its slightly higher concentration, a study on the radiological and chemical risks that are caused due to the ingestion of uranium was assessed. Based on the radiological aspect, cancer mortality and its risks were assessed, wherein all of the samples were well within the acceptable limit of 10-4; therefore, consuming these water samples was radiologically safe. However, when the risk that was caused by chemical toxicity was assessed, a few samples exceeded the hazard quotient (HQ) value of more than 1, thus illustrating that individuals were vulnerable to chemical risk. This paper features assessments of uranium and its risks to public health in groundwater samples if it exceeded the safe limit. Additionally, it recognizes the value of periodically assessing and treating the area's drinking water sources. [ABSTRACT FROM AUTHOR]

A total of 8459 larval fish were collected in the southern East China Sea during the winter northeasterly monsoon season and the summer southwesterly monsoon seasons in 2008. They were composed of 184 species belonging to 105 families and 162 genera. The abundance in terms of CPUE (number of individuals/1000m³) of the larvae was about six times higher in the southwesterly monsoon season than that in the northeasterly monsoon season. The primary environmental factors affecting the larval abundance were found to be water temperature in the northeasterly monsoon season but food availability in the southwesterly monsoon season. Three larval fish assemblages were recognized; the inshore assemblage, the offshore assemblage, and the summer coastal assemblage. The distribution and species composition of the larvae in the assemblages reflected the hydrographic conditions and water currents resulted from the seasonal monsoons. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess and to validate the suitability of the stable nitrogen and carbon isotope signature as soil erosion indicators in a mountain forest site n South Korea. Our approach is based on the comparison of the isotope signature of "stable" landscape positions (reference sites), which are neither affected by erosion nor deposition, with eroding sites. For undisturbed soils we expect that the enrichment of δ15d N and δ13C with soil depth, due to fractionation during decomposition, goes in parallel with a decrease in nitrogen and carbon content. Soil erosion processes potentially weaken this correlation. 137Cs-method and the Revised Universal Soil Loss Equation are applied for the soil erosion quantification. The erosion rates obtained with the 137Cs method range from 0.9 t ha-1 yr-1 to 7 t ha-1 yr-1. Considering the steep slopes of up to 40 and the erosive monsoon events (R-factor of 6600 MJ mm ha-1 h-1 yr-1), the rates are plausible and within the magnitude of the RUSLE- modelled soil erosion rates, varying from 0.02 t ha-1 yr-1 to 5.1 t ha-1 yr-1. The soil profiles of the reference sites showed significant (p<0.0001) correlations between nitrogen and carbon content and its corresponding δ15N and δ13C signatures. In contrast, for the eroding sites this relationship was weaker and for the carbon not significant. These results verify the usefulness of the stable carbon isotope signature as qualitative indicator for soil disturbance. We could show further that the δ15N isotope signature can be used similarly for uncultivated sites. We thus propose that the stable δ15N and δ15C signature of soil profiles could serve as a tool confirming the accurate choice of the reference site in soil erosion studies using the 137Cs-method. [ABSTRACT FROM AUTHOR]

Wave data collected off Ratnagiri, west coast of India during 1 May 2010 to 30 April 2012 is used in the study. Seasonal and annual variation in wave data controlled by the local wind system such as sea breeze and land breeze, and remote wind generated long period waves observed along the west coast of India, is studied. Sea breeze plays an important role in determining the sea state during pre and post monsoon seasons and the maximum wave height is observed during peak hours of sea breeze at 15:00UTC. Long period waves (peak period over 13 s) are observed mainly during the pre and the post monsoon season. Maximum peak period observed during the study is 22 s and is in the month of October. Long period waves observed during the south west monsoon period of 2011 are identified as swell propagated from the Southern Ocean with an estimated travelling time of 5-6 days. The swells reaching the Arabian Sea from the South Indian Ocean and Southern Ocean, due to storms during the pre and post monsoon periods will modify the near surface winds, due to the dominant wave induced wind regime. Energy spectrum of observed waves indicates onset and decline of strong south west monsoon winds. Convergence of energy-containing frequency bands corresponding to short period waves (Tp < 8s) and long period waves (Tp > 13s) to intermediate period waves (8 < Tp < 13s) are observed at the end of the pre monsoon season; divergence is observed during the start of the post monsoon period from intermediate period waves to short period waves and long period waves. South west monsoon period is characterized by the energy corresponding to the frequency band of intermediate period waves along the west coast of India. [ABSTRACT FROM AUTHOR]

This paper is written to commemorate the 10th anniversary of academician Ye Duzheng (Yeh T.C.) pass away and his great contributions to the development of atmospheric dynamics. Under the inspiration and guidance of the theory of Rossby wave energy dispersion, remarkable progresses have been made in research on planetary wave dynamics and teleconnections of atmospheric circulation anomalies. This paper aims to make a brief review of the studies on the propagating characteristics of quasi-stationary planetary waves in a three-dimensional spherical atmosphere and the dynamic processes of the interannual and interdecadal variabilities of the East Asian summer and winter monsoon systems. Especially, this paper systematically reviews the progresses of the studies on the impacts of the interannual and interdecadal variabilities of the East Asia/Pacific (EAP) pattern teleconnection wave train propagating along the meridional direction over East Asia and the "Silk Road" pattern teleconnection wave train propagating along the zonal direction within the subtropical jet from West Asia to East Asia on the East Asian summer monsoon system and the summer precipitation variability in China, under the guidance of the theory of Rossby wave energy dispersion. Moreover, this paper reviews the dynamic processes of the impact of the interannual and interdecadal oscillations of the propagating waveguides of boreal quasi-stationary planetary waves on the variability of the East Asian winter monsoon system. [ABSTRACT FROM AUTHOR]

Background The effects of small-scale disturbances, such as monsoon, are understudied in tropical regions. The storms associated with monsoon events not only modify the local macroalgal community structure, but also reveal the continuation of short-term recolonisation. Thus, this study aims to determine the variation in species, assemblage and cover of macroalgae during the monsoonal cycle from 2015 to 2016. This paper presents data on the spatial and temporal distribution of benthic macroalgae along the coastline of Johor, Malaysia. The information is presented as raw and partially-processed data, which summarises the cover and frequency of macroalgae at the respective study sites. This paper describes an important set of data that can be used further for in-situ experiments on the effects of environmental disturbances towards pioneer and climax species in tropical areas. [ABSTRACT FROM AUTHOR]

Three hindcast simulations of the global ocean circulation differing by resolution (1=4 or 1=12°) or parameterization or atmospheric forcing are used to study the fast interactions between the large anticyclonic eddies generated by the Somali Current system during the Southwest Monsoon. The present investigation of the Somalian coherent eddy structures allows us to identify the origin and the subsequent development of the cyclones flanked upon the Great Whirl (GW) previously identified by Beal and Donohue (2013) in satellite observations and to establish that similar cyclones are also flanked upon the Southern Gyre (SG). These cyclones are identified as major actors in mixing water masses within the large eddies and oshore the coast of Somali. All three simulations bring to light that during the period when the Southwest Monsoon is well established, the SG moves northward along the Somali coast and encounter the GW. The interaction between the SG and the GW is a collision without merging, collision during which the GW is pushed to the east of Socotra Island, sheds several smaller patches of anticyclonic vorticity, and often reforms into the Socotra Eddy, thus proposing a formation mechanism for the Socotra Eddy. During this process, the GW gives up its place to the SG which in turn becomes a new Great Whirl. This process is robust throughout the three simulations. [ABSTRACT FROM AUTHOR]

Largely depending on meltwater from the Hindukush-arakoram-imalaya, withdrawals from the upper Indus basin (UIB) contribute to half of the surface water availability in Pakistan, indispensable for agricultural production systems, industrial and do- mestic use and hydropower generation,Despite such importance, a comprehensive assessment of prevailing state of relevant climatic variables determining the water availability is largely missing,Against this background, we present a comprehensive hydroclimatic trend analysis over the UIB, including for the first time observations from highaltitude automated weather stations,We analyze trends in maximum, minimum and mean temperatures (Tx, Tn, and Tavg, respectively), diurnal temperature range (DTR) and precipitation from 18 stations (1250-4500ma.s.l.) for their overlapping period of record (1995-2012), and separately, from six stations of their long term record (1961- 2012),We apply Mann-Kendall test on serially independent time series to assess existence of a trend while true slope is estimated using Sen's slope method,Further, we statistically assess the spatial scale (field) significance of local climatic trends within ten identified sub-regions of UIB and analyze whether the spatially significant (field significant) climatic trends qualitatively agree with a trend in discharge out of corresponding sub-region,Over the recent period (1995-2012), we find a well agreed and mostly field significant cooling (warming) during monsoon season i.e,July-October (March-May and November), which is higher in magnitude relative to long term trends (1961-2012),We also find general cooling in Tx and a mixed response in Tavg during the winter season and a year round decrease in DTR, which are in direct contrast to their long term trends,The observed decrease in DTR is stronger and more significant at high altitude stations (above 2200ma.s.l.), and mostly due to higher cooling in Tx 25 than in Tn,Moreover, we find a field significant decrease (increase) in late-monsoonal precipitation for lower (higher) latitudinal regions of Himalayas (Karakoram and Hindukush), whereas an increase in winter precipitation for Hindukush, western- and whole Karakoram, UIB-Central, UIB-West, UIB-West-upper and whole UIB regions,We find spring warming (field significant in March) and drying (except for Karakoram and its sub-regions), and subsequent rise in early-melt season flows,Such early melt response together with effctive cooling during monsoon period subsequently resulted in a substantial drop (weaker increase) in discharge out of higher (lower) latitudinal regions (Himalaya and UIB-West-lower) during late-melt season, particularly during July,These discharge tendencies qualitatively diff to their long term trends for all regions, except for UIB-West-upper, western-Karakorum and Astore,The observed hydroclimatic trends, being driven by certain changes in the monsoonal system and westerly disturbances, indicate dominance (suppression) of nival (glacial) runoff regime, altering substantially the overall hydrology of UIB in future,These findings largely contribute to address the hydroclimatic explanation of the "Karakoram Anomaly". [ABSTRACT FROM AUTHOR]

The East China Sea (ECS) and the South China Sea (SCS) are two major marginal seas of the north Pacific with distinct seasonal primary productivity. Based upon field observation in December 2008--January 2009 covering both the ECS and the northern SCS (NSCS) in wintertime, we examined southward long-range nutrient-transport from the ECS to the northeast SCS (NESCS) carried by the China Coastal Current (CCC) driven by the northeast prevailing monsoon. These nutrients escaped from the cold ECS shelf to refuel the primary production on the NESCS shelf where river-sourced nutrients were limited yet water temperature remained favorable. By coupling the field observation of nitrate+nitrite (DIN) with the volume transport of the CCC, we derived a first order estimate of DIN flux of ~1430±260mol s-1. This DIN flux was ~7 times the wintertime DIN input from the Pearl River, a primary riverine nutrient source to the NSCS. By assuming DIN was the limiting nutrient, such southward DIN transport would have stimulated ~8.8±1.6x1011 gC of new production (NP), accounting for ~>58±10% of the total NP or ~38±7-24±4% of primary production on the NESCS shelf shallower than 100 m. [ABSTRACT FROM AUTHOR]

An eddy-resolving coupled physical-biological ocean model has been employed to investigate the physical influences on phytoplankton blooms in the South China Sea during 2000-2007. The model captures the seasonal and interannual variability of surface chlorophyll distribution associated with mesoscale eddies, ocean circulation and up-welling generated by the monsoon winds. The model also reproduces the high chlorophyll distributions in two coastal upwelling regions: the northwestern Luzon in winter and the eastern coast of Vietnam in summer. To the northwest of Luzon, the monsoon driven-upwelling, anticyclonic eddies, and the intrusion of the Kuroshio have a large impact on the winter phytoplankton bloom. The model shows the winter phytoplankton bloom is induced by the shallow nutricline depth under the northeast monsoon. Strong vertical motions at the edge of anticyclonic eddies enhance the phytoplankton bloom and produce the filamentary structure. Off the eastern coast of Vietnam, the monsoon-driven upwelling and anticyclonic circulation control the high chlorophyll distribution in summer. During the southwest monsoon, strong offshore Ekman transport and up-welling occur and increase the surface chlorophyll. The high chlorophyll is advected from the coast to open ocean by the strong offshore circulation. [ABSTRACT FROM AUTHOR]

This study reports abundance and distribution of gaseous NH3 and particulate Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed at Delhi. Gaseous NH3 and particulate Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed concentrations were measured during pre monsoon, monsoon and postmonsoon seasons of the years 2010 and 2011. Average concentrations of gaseous NH3 during premonsoon, monsoon and post monsoon seasons were recorded as 26.4, 33.2 and 32.5 µgm-3, respectively. Gaseous NH3 concentrations were the highest during monsoon due to decay and decomposition of plants and other biogenic material under wet conditions which emit NH3. The results showed that particulate Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed was always lower than the gaseous NH3 during all the seasons. The concentrations of particulate Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed were recorded as 11.6, 22.9 and 8.5 µgm-3 during premonsoon, monsoon and postmonsoon seasons, respectively. The percent fraction of particulate Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed was noticed highest during monsoon season due to increased humidity levels. On an average, 33.3% of total N-NHx was present as particulate Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed . Higher concentrations of NH3 noticed during night time may be due to stable atmospheric conditions. Study highlighted that as compared to rural sites, urban sites showed higher concentrations of gaseous NH3 in India which may be due to higher population density, human activities and poor sanitation arrangements. [ABSTRACT FROM AUTHOR]

Intraseasonal and diurnal variations are two basic periodic oscillations in global/regional climate and weather. To investigate their joint impacts over East Asia, this paper categorizes the boreal summer intraseasonal oscillations (ISOs) in 1998–2019 into two groups with different diurnal cycles. It is shown that the active ISOs with large diurnal cycles feature a northwestward-moving anomalous anticyclone with strong southerlies at the western flank. These ISOs have in-phase patterns of geopotential height anomaly between low and midlatitudes over East Asia, associated with the simultaneous expansions of the western Pacific subtropical high (WPSH) and South Asian high (SAH). They couple with the anomalous ABL heating by daytime solar radiation over East Asia, which acts to enhance monsoon southerlies at midnight. The nocturnally strengthened southerlies facilitate dynamic lifting, moisture transport, and convective instability for producing midnight to morning rainfall at their northern terminus, thereby yielding a remarkable northward propagation of the monsoon rain belt. In contrast, the other ISOs with small diurnal cycles are related to a westward-moving anomalous anticyclone, while the WPSH and SAH have relatively small expansions and the westerly trough is active at middle latitudes. They lead to the dipole patterns of geopotential height anomaly and weak ABL heating over East Asia. The daily-mean southerlies and moisture conditions as well as their nocturnal enhancements are relatively weak, and thus, the northward shift of the monsoon rain belt is less pronounced. These results highlight that the large-scale conditions of ISOs can be distinguished by their different couplings with regional-scale diurnal forcings, which help the understanding and prediction of multiscale rainfall activities. [ABSTRACT FROM AUTHOR]

The article discusses research on the impact of vegetation on intertropical convergence zone (ITCZ) and South Asian monsoon. The study used the Hadley Centre Climate Model (HadCM3) to analyze extra-tropical vegetation dynamics. Results show that the changes in the said vegetation systems may contribute in intensifying the South Asian monsoon.

The upper ocean circulation in the South China Sea (SCS) is driven by the Asian monsoon, the Kuroshio intrusion through the Luzon Strait, strong tidal currents, and a complex topography. Here, we demonstrate the benefit of assimilating along-track altimeter data into a nested configuration of the HYbrid Coordinate Ocean Model that includes tides. Including tides in models are important because they interact with the main circulation. However, assimilation of altimetry data into a model including tides is challenging because tides and mesoscales features contribute to the elevation of ocean surface at different time scales and require different corrections. To address this issue, tides are filtered out of the model output and only the mesoscale variability is corrected with a computationally cheap data assimilation method: the Ensemble Optimal Interpolation (EnOI). The method uses a running selection of members to handle the seasonal variability and assimilates the track data asynchronously. The data assimilative system is tested for the period 1994-1995, during which time a large number of validation data are available. Data assimilation reduces the Root Mean Square Error of Sea Level Anomalies from 9.3 cm to 6.9 cm and improves the representation of the mesoscale features. With respect to the vertical temperature profiles, the data assimilation scheme improves the results at intermediate depth, but a slight degradation of the results at the surface is noted. The comparison to surface drifters shows an improvement of surface current by approximately -8.3%, with largest improvements in the Northern SCS and east of Vietnam. [ABSTRACT FROM AUTHOR]

Using the general circulation model ECHAM5/JSBACH, we investigate the biogeophysical effect of large-scale afforestation and deforestation in the Asian monsoon domain on present-day and mid-Holocene climate. We demonstrate that the applied land cover change does not only modify the local climate but also change the climate in North Africa and the Middle East via teleconnections. Deforestation in the Asian monsoon domain enhances the rainfall in North Africa. In parts of the Sahara summer precipitation is more than doubled. In contrast, afforestation strongly decreases summer rainfall in the Middle East and even leads to the cessation of the rainfall-activity in some parts of this region. Regarding the local climate, deforestation results in a reduction of precipitation and a cooler climate as grass mostly has a higher albedo than forests. However, in the core region of the Asian monsoon the decrease of evaporative cooling in the monsoon season overcompensates this signal and results in a net warming. Afforestation has mainly the opposite effect, although the pattern of change is less clear. It leads to more precipitation in most parts of the Asian monsoon domain and a warmer climate except for the southern regions where a stronger evaporation decreases near-surface temperatures in the monsoon season. When prescribing mid-Holocene insolation, the pattern of local precipitation change differs. Afforestation particularly increases monsoon rainfall in the region along the Yellow River which was the settlement area of major prehistoric cultures. In this region, the effect of land cover change on precipitation is half as large as the orbitally-induced precipitation change. Thus, our model results reveal that mid- to late-Holocene land cover change could strongly have contributed to the decreasing Asian monsoon precipitation during the Holocene known from reconstructions. [ABSTRACT FROM AUTHOR]