Search

Evaporation from water surfaces is influencing many environmental science processes. Evaporation from pan data is not available as the most well-known method of determining evaporation in many areas, and therefore, the application of experimental mathematical equations in this field is considered. Most of the data for extracting these equations did not belong to cold regions, and as a result, the accuracy of these equations in cold regions has low reliability. In this study, the equations of Trabert (Meteorol Z 13:261–263, 1896), Kohler (Tech Rep Geol Survey Prof Paper 269:127–148, 1954), Kohler et al. (Evaporation from pans and lakes, US Government Printing Office, Washington, 1955), Papadakis (Soil Sci 93:76, 1961), Ântal (Evapotranspiration from com field. Term paper submitted for Dr. R. F. Dale's Agronomy 537 class. Received from personal communication with Dr. Dale (Dept. of Agronomy, Purdue, 1973), Linacre (Agric Meteorol 18:409–424, 1977), Linacre (Water Int 19:5–14, 1994) in Two default and revised modes (14 equations in total) have been used to determine evaporation in cold regions (Emberger climate classifications). Performance index (PI) as an error metric was used to analyze the efficiency of the equations. Findings show that in the absence of proper datasets for revision, Kohler et al. (Evaporation from pans and lakes, US Government Printing Office, Washington, 1955) and Papadakis (Soil Sci 93:76, 1961) equations are more proper options for determining evaporation in cold regions. The revision process increased the efficiency of all equations, with the slightest improvement for Papadakis (Soil Sci 93:76, 1961) and the most improvement for Trabert (Meteorol Z 13:261–263, 1896). According to the behavior of Papadakis (Soil Sci 93:76, 1961) equation in the revision process and its efficiency in both default and revision modes, it can be considered a firm equation in the cold region. The findings reveal that the revised equations have little efficiency difference. It indicates that in cold regions, the influence of the default parameters of the equations on efficiency is more significant than their mathematical formula of the equation. Also, the revision has led to Trabert (Meteorol Z 13:261–263, 1896) equation with relatively good results due to less relative flexibility than other equations. Therefore, it can be concluded that the essential factor to increase the reliability of the application of experimental mathematical equations in determining evaporation from the pan is the use of revised equations with data from cold regions. In addition, among all the equations studied, the revised Kohler et al. (Evaporation from pans and lakes, US Government Printing Office, Washington, 1955) equation was recognized as the most efficient equation for determining evaporation from the pan in the cold regions studied. [ABSTRACT FROM AUTHOR]

In this paper, we make use of the monoHölder nature of surface air temperature data to recapture the Köppen-Geiger climate classification in Europe. Using data from the European Climate Assessment and Dataset (ECA&D), we first show that the Hölder exponents of surface air temperature data are statistically related to pressure anomalies. Then, we establish a climate classification based on these Hölder exponents in such a way that it allows to recover the Köppen-Geiger climate classification. We show that the two classifications match for a vast majority of stations, and we corroborate these observations with a confirmation test. We compare these results with those obtained with another dataset (NCEP-NCAR Reanalysis Project) to show that the new classification is still well-adapted, before eventually discussing these findings. [ABSTRACT FROM AUTHOR]

In Turkey, four degree-day regions stated in the standards are used in building heating energy load calculations. Deficiencies about the degree-day regions are mentioned in some other studies. In this paper, a different climatic zone approach suggested by International Energy Agency (IEA) regarding both heating and cooling degree-day data, derived from Typical Meteorological Year (TMY) data, is used. Results are presented graphically and compared with the current regulations. The second degree-day region, according to Turkish Standard (Thermal Insulation Requirements for Buildings (TS 825)), is divided into four climatic zones with the method proposed by IEA. Difference between monthly outdoor temperature values of the second degree-day region and cities in this region is up to 6.4 °C which is high. The conclusion of this study is that the climatic variables should be evaluated in detail, and a new climatic zone study should be done regarding both heating and cooling loads. This will imply new building energy load calculations for all cities in Turkey. [ABSTRACT FROM AUTHOR]

Worldwide, climate classification schemes are useful for characterizing the biological potentials of terrestrial ecosystems. Among these schemes, the Köppen-Geiger global climate classification has increasingly been used in a wide range of environmental fields. However, the resulting climate information is insufficient to fully portend the dynamics of ecosystem components such as vegetation gradients and water resources. To enhance the interpretability of this climate information, research-driven frameworks are needed to connect terrestrial vegetation and water resource signals to the Köppen-Geiger climate classes. Hence, this study developed a probabilistic framework for characterizing vegetation and water resources variability within the Köppen-Geiger climate classification system. The framework combines an application of entropy theory with multivariate logistic models, and it uses variables including half-degree gridded precipitation, surface temperature, leaf area index, and liquid water equivalence anomalies. Explicitly, entropy-based disorder index (DI) values are quantified for individual variables and thresholds of DI percentiles are used to discretize vegetation and water resources variability zones at the global scale. Multivariate logistic models are later applied to grid-level DI zone attributes and long-term average values to predict Köppen-Geiger climate classes. The statistical evaluation sustained variable models' likelihoods (0.04≤McFadden's pseudo-R2≤0.92) but consistent estimates (0.87≤Count R2≤0.99) within the global climate classes. The developed framework could be an avenue to improve the interpretability of Köppen-Geiger climate classes by providing a probabilistic insight into vegetation and water resources change at regional, continental, or global levels. [ABSTRACT FROM AUTHOR]

The observed continuous rise in the frequency of extreme heat events in South America (SA) poses a serious challenge for public health. However, there is a lack on the understanding of the large-scale and long-term variability and trends of thermal stress in this continent. Accordingly, here we developed the first comprehensive bioclimatology of thermal stress over SA during the past four decades. Consecutive heat stress hours were analyzed using the Universal Thermal Climate Index (UTCI) from ERA5-HEAT reanalysis according to the Köppen–Geiger climate classification and also focusing on the 31 most populated cities of SA. Results show an inland/coastline contrast and a marked latitudinal northward increase in the number of hours under heat stress. Heat stress hotspots are located mostly around the Amazon, northern and central parts of SA with 26–35% of the hours between 1979 and 2020 under strong heat stress. The annual number of hours within heat stress increased significantly between 1979 and 2020, varying from + 1.16 h/year to + 8.25 h/year depending on the Köppen–Geiger class. The past 20 years (2000 forward) presented not only more consecutive hours under heat stress than the previous two decades in all the analyzed cities, but also a higher persistence of such conditions. The bioclimatology of thermal stress developed here may provide important guidelines to decision-makers for exploring adaptation strategies to increase societal resilience. [ABSTRACT FROM AUTHOR]

How strong is the resemblance between two states of the atmosphere leading to the same outcome? In the following pages this question was addressed by studying the resemblance of the surface pressure fields, obtained by NCEP reanalyses, corresponding to “intense” precipitation events over 5 Italian climatic areas. Such “intense” precipitation events were selected by means of 45 daily precipitation records covering the period from 1951 to 2000. Two pressure patterns that resemble one another are termed soft-analogues in this paper. The mathematical measures used to assess the difference between two pressure patterns were: the root-mean-square difference, the correlation, and the S1 score. The comparison outcomes were categorized into classes according to the previous measures. Once a couple of the pressure patterns were found to be good soft-analogues (that was a rare occurrence), these pressure patterns were compared with all pressure patterns excluded by the initial selection being not associated with intense precipitation events. The few soft-analogues associated with “intense” precipitation events were found to be also soft-analogue to several, and sometimes a great deal of, pressure patterns not associated with the selected “intense” precipitation events. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of pluviometric precipitation time series obtained from 45 data collection points, with daily rain measurements (in mm), from 45 counties within the nine climatic regions of the state of São Paulo, mostly for the period of 1950–1997. São Paulo State (Brazil) is situated between the inter-tropical climatic zone, dominated by tropical and equatorial masses, and the sub-tropical climatic zone controlled by tropical and polar air masses. Due to this location the State can be divided into three climatic zones: south-east and south-west, which are permanently humid, and north with a well defined dry period. Rescaled range analysis, or R/S analysis, has been used to investigate the scale properties of the time series. We found two clear values for the Hurst exponent, one for a period of 10 to 200 days (H1), and another for a period above 210 days (H2). The value of H1 lies between 0.6 to 0.7 for all climatic zones indicating characteristics of persistence. However, H2 is (i) close to 0.5 for the littoral area, showing random characteristics, (ii) close to 0.6 for mountain areas, indicating persistence characteristics, and (iii) close to 0.4 for the plane area, irrespective of whether the climate is dry or humid, and shows anti-persistence characteristics. [ABSTRACT FROM AUTHOR]

Evaluating the interactions between cold requirements for leaf coloration and environmental cues is crucial for understanding the mechanisms of leaf senescence and accurately predicting autumn phenology. Based on remote sensing-derived and ground-observed leaf coloration dates for deciduous broadleaf forests during 1981–2014, we determined location-specific cold requirements for autumn leaf coloration and assessed their spatiotemporal changes. Then, we revealed the major environmental cues of cold requirements and their spatial differentiation. Results show that cold requirements have nonsignificant trends during the past decades at 57.9% of pixels. The interannual variation of cold requirements was mainly influenced by growing-season accumulated temperature (GDDgs) at 35.8% of pixels and accumulated growing season index (AGSI) at 23.2% of pixels, but less affected by leaf unfolding and low precipitation index (LPI). The increase in GDDgs or AGSI may decrease cold requirements, and vice versa. The spatial differentiations of the effects of GDDgs and AGSI depend highly on local summer temperature among climatic classifications with similar humidity conditions. Specifically, the effects of GDDgs on cold requirements concentrated in humid regions with warmer summers, while that of AGSI mainly occurred in humid and winter dry regions with cooler summers. Higher summer temperatures would strengthen the effects of GDDgs and reduce the effects of AGSI on cold requirements. These findings deepen the understanding of the influences of environmental factors on leaf senescence progress and suggest that the shifts of factors affecting cold requirements under global warming may enlarge the uncertainty in predicting autumn leaf coloration dates. [ABSTRACT FROM AUTHOR]

In this paper, the importance of investigation on terrestrical processes in arid areas for mankind's living environment protection and local economy development as well as its present state of the art are elucidated. A coupling model, which evaluates heat, mass, momentum and radiative fluxes in the SPAC system, is developed for simulating microclimate over plant and bare soil. Especially, it is focussed on the details of turbulence transfer. For illustration, numerical simulation of the water-heat exchange processes at Shapotou Observatory, CAS, Ninxia Province are conducted, and the computational results show that the laws of land-surface processes are rather typical in the arid areas. [ABSTRACT FROM AUTHOR]

Providing comfortable thermal conditions for users of open spaces is vitally important for improving the quality of urban life. Thermal comfort can be defined through environmental, individual, and subjective variables. The Olgyay bioclimatic chart is an outdoor thermal comfort analysis tool, connecting temperature with relative humidity. The application of this tool is still limited to hot humid climates only where minimal differences between indoor and outdoor temperatures exist. The novelty of this work is to propose adaptations to the Olgyay bioclimatic chart, taking into consideration different climatic classifications. In addition, urban plantation is examined for its influence on thermal comfort through the bioclimatic chart. The method adopted in this research consists of field measurements of the microclimatic variables in the examined places. In response, a new graphic model is proposed with a range of thermal comfort zone and analysis of the data obtained. The neighborhood of Humaitá in Rio de Janeiro in Brazil is applied as a case study to validate the proposed approach. Insights into this work reveal that the urban plantation is contributing to the reduction of air temperature and the increase of relative air humidity; however, this contribution is insufficient to reach the thermal comfort conditions. [ABSTRACT FROM AUTHOR]

Feddema’s generic climate classification method is applied to study climate and climate change in the Austrian-Swiss region of the European Alps during the course of the twentieth century. A fine-tuned version of it is also tested in addition to the original scheme. Monthly precipitation and air temperature data at a spatial resolution of 10′ × 10′ are taken from the Climatic Research Unit TS 1.2 database to construct 30- and 50-year period averages. It is shown that the alpine climate is sufficiently heterogeneous to make it unnecessary to perform fine-tuning of the original scheme for its characterization on the meso-β scale (20-200 km). It is also demonstrated that data organizational effects are much less intense than the effects caused by the fine-tuning. The area heterogeneity of climate and climate change types is the highest in the vicinity of lakes (Austria: Lake Constance; Switzerland: Lakes Geneva, Neuchâtel, Biel, Zurich, and Constance) and along river valleys (Austria: the Danube, Drava, and Mur; Switzerland: the Aare and Ticino). The dominant climate change process was drying in Austria and warming in Switzerland. Large areas characterized by cold and saturated climate in the Central Eastern Alps did not experience climate change during the twentieth century. [ABSTRACT FROM AUTHOR]

Future changes in large-scale climatology and perturbation may have different impacts on regional climate change. It is important to understand the impacts of climatology and perturbation in terms of both thermodynamic and dynamic changes. Although many studies have investigated the influence of climatology changes on regional climate, the significance of perturbation changes is still debated. The nonlinear effect of these two changes is also unknown. We propose a systematic procedure that extracts the influences of three factors: changes in climatology, changes in perturbation and the resulting nonlinear effect. We then demonstrate the usefulness of the procedure, applying it to future changes in precipitation. All three factors have the same degree of influence, especially for extreme rainfall events. Thus, regional climate assessments should consider not only the climatology change but also the perturbation change and their nonlinearity. This procedure can advance interpretations of future regional climates. [ABSTRACT FROM AUTHOR]

Although it is evident that Nepal has an extremely wide range of climates within a short latitudinal distance, there is a lack of comprehensive research in this field. The climatic zoning in a topographically complex country like Nepal has important implications for the selection of scientific station network design and climate model verification, as well as for studies examining the effects of climate change in terms of shifting climatic boundaries and vegetation in highly sensitive environments. This study presents a new high-resolution climate map of Nepal on the basis of long-term (1981-2010) monthly precipitation data for 240 stations and mean air temperature data for 74 stations, using original and modified Köppen-Geiger climate classification systems. Climatic variables used in Köppen-Geiger system were calculated (i) at each station and (ii) interpolated to 1-km spatial resolution using kriging which accounted for latitude, longitude, and elevation. The original Köppen-Geiger scheme could not identify all five types of climate (including tropical) observed in Nepal. Hence, the original scheme was slightly modified by changing the boundary of coldest month mean air temperature value from 18 °C to 14.5 °C in order to delineate the realistic climatic condition of Nepal. With this modification, all five types of climate (including tropical) were identified. The most common dominant type of climate for Nepal is temperate with dry winter and hot summer (Cwa). [ABSTRACT FROM AUTHOR]

In cities in temperate climate zones, the elderly, disabled and socially deprived are most vulnerable to extreme heat, as witnessed by increased mortality rates during heat waves in Europe and North America. Many cities, however, lag behind in the protection of vulnerable citizens against heat stress, an issue gaining importance in the face of climate change, ongoing urbanization and an ageing population. This raises questions as to who bears responsibility for the protection of these vulnerable citizens. Should they protect themselves, or is this a collective responsibility? Which public and private organizations could take on this collective responsibility? This study explores potential governance arrangements between public and private actors by analysing the perceived responsibilities and their underlying considerations of public and private actors through two multi-stakeholder workshops and one focus group held in two Dutch cities. Furthermore, the study looks into what can be learned from ten foreign cities where a heat stress policy has been implemented, with respect to the concrete shaping of responsibilities and how trade-offs in considerations are dealt with. The research reveals that because of conflicting considerations there is disagreement as to who bears responsibility for the implementation of health care measures, and it shows how this might be resolved through differentiated approaches for an active outreach to vulnerable citizens. We conclude that "cool" governance suggests extensive public responsibilities throughout the policy process, but that policy implementation needs public-private networks tailored to these differentiated approaches. [ABSTRACT FROM AUTHOR]

For investigating aridity in Vojvodina, two parameters were used: the De Martonne aridity index and the Pinna combinative index. These indices were chosen as the most suitable for the analysis of climate in Vojvodina (a region in northern part of Serbia). Also, these indices were calculated from data obtained from 10 meteorological stations for the period from 1949 to 2006. The spatial distribution of the annual and seasonal De Martonne and the Pinna combinative indices as well as the mean monthly values of the De Martonne index and aridity trends of these indices are presented. There were two, four, and five types of climate on a yearly, seasonal, and monthly basis in Vojvodina, according to the De Martonne climate classification which consists of a total of seven types. In addition, semi-humid and humid climate types were represented in the region, on a yearly basis. The winter season was dominated by wetter types of climate, while the summer season was characterized by drier ones. During the spring and autumn seasons, there were types of climate which range between both aforementioned types. Two out of three climate types, which can be identified using the Pinna combinative index, were registered in Vojvodina region. The most dominant climate type was the semidry Mediterranean with formal Mediterranean vegetation, while the humid type was only identified in one small part of southwestern Vojvodina. The calculated values of both aridity indices showed that there were no annual trends. Therefore, it can be considered that there were no recent aridity changes during the observed period. For paleoclimate, the general story is more complex. The lack of aridity trends in the recent period from 1949 to 2006 supports the fact that Vojvodina has very well preserved loess-palaeosol sequences from the Middle and Late Pleistocene, which indicates that crucial point for their preservation was caused by the weak aridity variability in the region. [ABSTRACT FROM AUTHOR]

Human-induced climate change causes significant changes in local climates, which in turn lead to changes in regional climate zones. Large shifts in the world distribution of Köppen-Geiger climate classifications by the end of this century have been projected. However, only a few studies have analysed the pace of these shifts in climate zones, and none has analysed whether the pace itself changes with increasing global mean temperature. In this study, pace refers to the rate at which climate zones change as a function of amount of global warming. Here we show that present climate projections suggest that the pace of shifting climate zones increases approximately linearly with increasing global temperature. Using the RCP8.5 emissions pathway, the pace nearly doubles by the end of this century and about 20% of all land area undergoes a change in its original climate. This implies that species will have increasingly less time to adapt to Köppen zone changes in the future, which is expected to increase the risk of extinction. [ABSTRACT FROM AUTHOR]

The article reports on the research conducted by Stephanie McAfee and Joellen Russell of the University of Arizona regarding the climate variability in Northerm Hemisphere. Researchers predicted that as the Earth warms, the Northern Annular Mode (NAM), a flipflopping pattern of climate variability in the Northern Hemisphere, will flop more firmly to its low-pressure-near-the-pole state. They concluded that spring weather in the southwestern U.S. will be sensitive to the NAM's behaviour and an intensified NAM leads to warm weather coming earlier, shortening the winter rainy season and leading to drier weather that year.

Analysis of numbers of invasive species (insects, plants, plant diseases) in each of Chinese provinces and the world’s climatic zones respectively, demonstrated positive correlations between diversity of bioinvasion and air temperature and precipitation (the two main criteria for classifying world climate types). When the air temperature is within the range of 1–25°C, the degree of diversity of invasive alien species increases exponentially with air temperature. However, when the air temperature falls outside the range of 1–25°C, the diversity of harmful invasive alien species changes with air temperature in a parabolic pattern, showing a “mid-latitude bulge”. Namely, when air temperatures are too high or too low, a lower average invasion frequency of harmful alien species is observed. Invasion by harmful invasive alien species is more weakly related to precipitation. Different climatic zones showed dramatic differences in resistance to the invasion of invasive alien species due to their different characteristic climatic factors, mainly including air temperature and precipitation. [ABSTRACT FROM AUTHOR]

Ten wheat production sites of Pakistan were categorized into four climatic zones i.e. arid, semi-arid, sub-humid and humid to explore the vulnerability of wheat production in these zones to climate change using CSM-Cropsim-CERES-Wheat model. The analysis was based on multi-year (1971–2000) crop model simulation runs using daily weather series under scenarios of increased temperature and atmospheric carbon dioxide concentration (CO2) along with two scenarios of water management. Apart from this, sowing date as an adaptation option to offset the likely impacts of climate change was also considered. Increase in temperature resulted in yield declines in arid, semi-arid and sub-humid zone. But the humid zone followed a positive trend of gain in yield with rise in temperature up to 4°C. Within a water regime, increase in CO2 concentration from 375 to 550 and 700 ppm will exert positive effect on gain in wheat yield but this positive effect is significantly variable in different climatic zones under rainfed conditions than the full irrigation. The highest response was shown by arid zone followed by semi-arid, sub-humid and humid zones. But if the current baseline water regimes (i.e. full irrigation in arid and semi-arid zones and rainfed in sub-humid and humid zones) persist in future, the sub-humid zone will be most benefited in terms of significantly higher percent gain in yield by increasing CO2 level, mainly because of its rainfed water regime. Within a CO2 level the changes in water supply from rainfed to full irrigation shows an intense degree of responsiveness in terms of yield gain at 375 ppm CO2 level compared to 550 and 700 ppm. Arid and semi-arid zones were more responsive compared to sub-humid and humid zones. Rise in temperature reduced the length of crop life cycle in all areas, though at an accelerated rate in the humid zone. These results revealed that the climatic zones have shown a variable intensity of vulnerability to different scenarios of climate change and water management due to their inherent specific and spatial climatic features. In order to cope with the negative effects of climate change, alteration in sowing date towards cooler months will be an appropriate response by the farmers. [ABSTRACT FROM AUTHOR]

The study of climate changes in India and search for robust evidences are issues of concern specially when it is known that poor people are very vulnerable to climate changes. Due to the vast size of India and its complex geography, climate in this part of the globe has large spatial and temporal variations. Important weather events affecting India are floods and droughts, monsoon depressions and cyclones, heat waves, cold waves, prolonged fog and snowfall. Results of this comprehensive study based on observed data and model reanalyzed fields indicate that in the last century, the atmospheric surface temperature in India has enhanced by about 1 and 1.1°C during winter and post-monsoon months respectively. Also decrease in the minimum temperature during summer monsoon and its increase during post-monsoon months have created a large difference of about 0.8°C in the seasonal temperature anomalies which may bring about seasonal asymmetry and hence changes in atmospheric circulation. Opposite phases of increase and decrease in the minimum temperatures in the southern and northern regions of India respectively have been noticed in the interannual variability. In north India, the minimum temperature shows sharp decrease of its magnitude between 1955 and 1972 and then sharp increase till date. But in south India, the minimum temperature has a steady increase. The sea surface temperatures (SST) of Arabian Sea and Bay of Bengal also show increasing trend. Observations indicate occurrence of more extreme temperature events in the east coast of India in the recent past. During summer monsoon months, there is a decreasing (increasing) trend in the frequency of depressions (low pressure areas). In the last century the frequency of occurrence of cyclonic storms shows increasing trend in the month of November. In addition there is increase in the number of severe cyclonic storms crossing Indian Coast. Analysis of rainfall amount during different seasons indicate decreasing tendency in the summer monsoon rainfall over Indian landmass and increasing trend in the rainfall during pre-monsoon and post-monsoon months. [ABSTRACT FROM AUTHOR]

Models and palaeoclimate data suggest that the tropical Pacific climate system plays a key part in the mechanisms underlying orbital-scale and abrupt climate change. Atmospheric convection over the western tropical Pacific is a major source of heat and moisture to extratropical regions, and may therefore influence the global climate response to a variety of forcing factors. The response of tropical Pacific convection to changes in global climate boundary conditions, abrupt climate changes and radiative forcing remains uncertain, however. Here we present three absolutely dated oxygen isotope records from stalagmites in northern Borneo that reflect changes in west Pacific warm pool hydrology over the past 27,000 years. Our results suggest that convection over the western tropical Pacific weakened 18,000–20,000 years ago, as tropical Pacific and Antarctic temperatures began to rise during the early stages of deglaciation. Convective activity, as inferred from oxygen isotopes, reached a minimum during Heinrich event 1 (ref. 10), when the Atlantic meridional overturning circulation was weak, pointing to feedbacks between the strength of the overturning circulation and tropical Pacific hydrology. There is no evidence of the Younger Dryas event in the stalagmite records, however, suggesting that different mechanisms operated during these two abrupt deglacial climate events. During the Holocene epoch, convective activity appears to track changes in spring and autumn insolation, highlighting the sensitivity of tropical Pacific convection to external radiative forcing. Together, these findings demonstrate that the tropical Pacific hydrological cycle is sensitive to high-latitude climate processes in both hemispheres, as well as to external radiative forcing, and that it may have a central role in abrupt climate change events. [ABSTRACT FROM AUTHOR]

The growing interest in and emphasis on high spatial resolution estimates of future climate has demonstrated the need to apply regional climate models (RCMs) to that problem. As a consequence, the need for validation of these models, an assessment of how well an RCM reproduces a known climate, has also grown. Validation is often performed by comparing RCM output to gridded climate datasets and/or station data. The primary disadvantage of using gridded climate datasets is that the spatial resolution is almost always different and generally coarser than climate model output. We have used a Bayesian statistical model derived from observational data to validate RCM output. We used surface air temperature (SAT) data from 109 observational stations in California, all with records of approximately 50 years in length, and created a statistical model based on this data. The statistical model takes into account the elevation of the station, distance from coastline, and the NOAA climate region in which the station resides. Analysis indicates that the statistical model provides reliable estimates of the mean monthly SAT at any given station. In our method, the uncertainty in the estimates produced by the statistical model are directly determined by obtaining probability density functions for predicted SATs. This statistical model is then used to estimate average SATs corresponding to each of the climate model grid cells. These estimates are compared to the output of the RCM to assess how well the RCM matches the observed climate as defined by the statistical model. Overall, the match between the RCM output and the statistical model is good, with some deficiencies likely due in part to the representation of topography in the RCM. [ABSTRACT FROM AUTHOR]

Tropical North African climate variability is investigated using a Sahel rainfall index and streamflow of the Nile River in the 20th century. The mechanisms that govern tropical North Africa climate are diagnosed from NCEP reanalysis data in the period 1958–1998: spatially – using composite and correlation analysis, and temporally – using wavelet co-spectral analysis. The Sahelian climate is characterised by a decadal rhythm, whilst the mountainous eastern and equatorial regions exhibit interannual cycles. ENSO-modulated zonal circulations over the Atlantic/Pacific sector are important for decadal variations, and create a climatic polarity between South America and tropical North Africa as revealed through upper-level velocity potential and convection patterns. A more localised N–S shift in convection between the Sahel and Guinea coast is associated with the African Easterly Jet. [ABSTRACT FROM AUTHOR]

Seven synoptic patterns responsible for heavy precipitation in Austria were identified with a trajectory clustering method. Back trajectories at different levels, at different times during each day, and from different locations in Austria were utilised together with one potential vorticity value. In addition, seven regions within Austria with similar daily precipitation were identified. The response of heavy precipitation in each of these regions to the synoptic patterns was studied. The results correspond to the synoptic experience and reflect known meteorological situations, such as southerly and northerly Stau or the Vb pattern. The analyses are based on the 15-year re-analysis of the ECMWF (1979–1993), used to calculate the back trajectories, and daily precipitation sums of 131 climate stations in Austria. This paves the way to future applications in climate change research, as the necessary input data are also available from global climate models. The clustering was performed with a promising new procedure, a combination of hierarchical and iterative (K-means) clustering. [ABSTRACT FROM AUTHOR]

Based on the study of several different-age shallow-water carbonate sediments from different regions, it is established that cyclothems formed in basins of arid and humid climatic zones differ in their composition and structure. It is shown that the influence of climate was indirect. The climate governed salinity (particularly, in extremely shallow-water settings of initial and terminal stages of the formation of cyclothems) and, thus, stimulated changes in the biota. The biota, in turn, controlled the composition of carbonate material and mechanisms of its sedimentation. [ABSTRACT FROM AUTHOR]

This study aims to demonstrate the potential of a process-based regional ecosystem model, LPJ-GUESS, driven by climate scenarios generated by a regional climate model system (RCM) to generate predictions useful for assessing effects of climatic and CO2 change on the key ecosystem services of carbon uptake and storage. Scenarios compatible with the A2 and B2 greenhouse gas emission scenarios of the Special Report on Emission Scenarios (SRES) and with boundary conditions from two general circulation models (GCMs) - HadAM3H and ECHAM4/OPYC3 - were used in simulations to explore changes in tree species distributions, vegetation structure, productivity and ecosystem carbon stocks for the late 21st Century, thus accommodating a proportion of the GCM-based and emissions-based uncertainty in future climate development. The simulations represented in this study were of the potential natural vegetation ignoring direct anthropogenic effects. Results suggest that shifts in climatic zones may lead to changes in species distribution and community composition among seven major tree species of natural Swedish forests. All four climate scenarios were associated with an extension of the boreal forest treeline with respect to altitude and latitude. In the boreal and boreo-nemoral zones, the dominance of Norway spruce and to a lesser extent Scots pine was reduced in favour of deciduous broadleaved tree species. The model also predicted substantial increases in vegetation net primary productivity (NPP), especially in central Sweden. Expansion of forest cover and increased local biomass enhanced the net carbon sink over central and northern Sweden, despite increased carbon release through decomposition processes in the soil. In southern Sweden, reduced growing season soil moisture levels counterbalanced the positive effects of a longer growing season and increased carbon supply on NPP, with the result that many areas were converted from a sink to a source of carbon by the late 21st century. The economy-oriented A2 emission scenario would lead to higher NPP and stronger carbon sinks according to the simulations than the environment-oriented B2 scenario. [ABSTRACT FROM AUTHOR]

Appreciable observational data were used to reveal zonal features of the formation of the chemical composition of waters in small lakes on the territory of European Russia along a transect from tundra to the arid zone. Inter-zonal variability in the parameters of the chemical composition of waters is determined. Zonal differentiation according to hydrochemical parameters is substantiated. The main differentiating elements of the chemical composition of waters in different natural-climatic zones are distinguished. The contribution of the main natural and anthropogenic factors, determining the present-day processes of water formation is analyzed. Different degrees of the effect of non-zonal factors (including anthropogenic ones) on the formation of the chemical composition of lake waters in the humid and arid zones are demonstrated. [ABSTRACT FROM AUTHOR]

The loss of stored water from surface water reservoirs through evaporation is inevitable and can be significant in arid and semi-arid climates. One way of compensating for this inevitable loss is to explicitly include the evaporation process in the reservoir planning analysis, thus ensuring that the resulting capacity estimate will be capable of meeting both the intended consumptive demands and the evaporative losses. However, because evaporation measurements are often unavailable and because there are few reservoir planning techniques that can explicitly accommodate evaporation consideration, this solution is often not applied. The result is that there is currently little guidance regarding the allowance for evaporation losses during reservoir planning in such regions. This study has used data from the Urmia region in Iran to develop a rule for evaporation correction during reservoir planning. The way to use the rule is explained and suggestions about how the study can be extended are offered. [ABSTRACT FROM AUTHOR]

The article discusses the development programs of developing nations on climate change. It reports on the new regulatory programme of the Mexican government that will lessen the projected emissions of the country by more than 6% over the next three years. The programme aims to demonstrate actual emissions reductions before the government of President Felipe Calderón ends in 2012. It is considered to be a way of proving which may consider the climate change issue and lay sound development foundation. China and India tend to submerge any gains with increasing cumulative emissions. It points out that emissions from developing countries exceed those of industrialized nations and are expected to increase twice as fast as those in developed countries.