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Transitional climate zone (TCZ) over East Asia is located between humid and arid regions, which is a highly sensitive and disaster-prone region especially under global climate change. Due to limited water resources, the atmospheric moisture availability has a dominant control on the precipitation variability. Hence, this study is motivated to reveal the key teleconnection patterns and associated moisture processes that govern the interannual variability of the summer precipitation over TCZ. In order to better diagnose moisture budget, the Lagrangian particle dispersion model FLEXPART is employed for quantifying contribution from moisture sources. Above all, the observational analysis highlights two critical modes, one is Eurasian teleconnection (EU) and the other is Circumglobal Teleconnection (CGT). As regards EU pattern, positive EU phase corresponds to ample precipitation in TCZ. In the presence of positive phase, it underlines a "+-+-" pattern of geopotential height anomalies stretching from western Europe to Mongolia plateau. In the context, the cyclonic flow and low pressure over Mongolia plateau act to enhance moisture flux from the west and the south and to prompt upward motions. Further moisture diagnoses illuminate largest increase of moisture uptake in monsoon dominated region, followed by the westerlies dominated region. However, the eventual contribution of summer monsoon is a little bit less than that of westerlies, due to the grand loss en route. In addition, the local evaporation exerts little impact. CGT propagates along the mid-latitude westerly jet, which is positively coupled with the precipitation in TCZ. Under the positive phase, there is an ascending motion over TCZ, which bears great resemblance to the EU case. However, unlike the result of moisture attribution in EU case, the southerly monsoon has the largest contribution followed by local effect, while the westerlies have little impact due to the cancellation of wetting and drying regimes along the pathway. [ABSTRACT FROM AUTHOR]

This paper attempts to provide some new understanding of the mechanical as well as thermal effects of the Tibetan Plateau (TP) on the circulation and climate in Asia through diagnosis and numerical experiments. The air column over the TP descends in winter and ascends in summer and regulates the surface Asian monsoon flow. Sensible heating on the sloping lateral surfaces appears from the authors’ experiments to be the major driving source. The retarding and deflecting effects of the TP in winter generate an asymmetric dipole zonal-deviation circulation, with a large anticyclone gyre to the north and a cyclonic gyre to the south. Such a dipole deviation circulation enhances the cold outbreaks from the north over East Asia, results in a dry climate in south Asia and a moist climate over the Indochina peninsula and south China, and forms the persistent rainfall in early spring (PRES) in south China. In summer the TP heating generates a cyclonic spiral zonal-deviation circulation in the lower troposphere, which converges toward and rises over the TP. It is shown that because the TP is located east of the Eurasian continent, in summertime the meridional winds and vertical motions forced by the Eurasian continental-scale heating and the TP local heating are in phase over the eastern and central parts of the continent. The monsoon in East Asia and the dry climate in middle Asia are therefore intensified. [ABSTRACT FROM AUTHOR]

The African continent is characterised by a wide range of hydroclimate regimes, ranging from humid equatorial West Africa to the arid deserts in the northern and southern subtropics. The livelihoods of much of its population are also vulnerable to future climate change, mainly through variability in rainfall affecting water resource availability. A growing number of data sources indicate that such hydroclimatic variability is an intrinsic component of Africa's natural environment. This paper, co-authored by members of the PAGES Africa 2k Working Group, presents an extensive assessment and discussion of proxy, historical and instrumental evidence for hydroclimatic variability across the African continent, spanning the last two millennia. While the African palaeoenvironmental record is characterised by spatially disjunctive datasets, with often less-than-optimal temporal resolution and chronological control, the available evidence allows the assessment of prominent spatial patterns of palaeomoisture variability through time. In this study, we focus sequentially on data for six major time windows: the first millennium CE, the Medieval Climate Anomaly (900–1250 CE), the Little Ice Age (1250–1750 CE), the end of the LIA (1750–1850 CE), the Early Modern Period (1850–1950), and the period of recent warming (1950 onwards). This results in a continent-wide synthesis of regional moisture-balance trends through history, allowing consideration of possible driving mechanisms, and suggestions for future research. [ABSTRACT FROM AUTHOR]

The vineyards in the south of Moldova are increasingly affected by climate change occurring over the last period. Reducing crop quality and quantity a hub of grape vineyards and affecting the occurrence of early winter frosts and excessive negative temperatures, the late spring frosts and drought of the vegetation period, result in significant losses for vineyard property. Witnessing lately to torrential rainfall, prolonged drought, excessive years of normal or dry years followed by rain. All these aspects influence of soil water reserves have mostly hydric deficit since June. The paper presents analysis of rainfall and soil humidity regime. For analysis of rainfall were recorded at weather station data used to SCDVV Bujoru. They collected soil samples monthly, on the horizon 0-100 cm, from 20 to 20 cm. With hydro index was calculated soil moisture in the soil available. Analyzed during the early vegetation period the soil water reserve is located in the humidity range of 55-70% of assets and soil water deficit is greatest in August. [ABSTRACT FROM AUTHOR]

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The article focuses on the changes in rainfall and relative humidity in river basins in northwest and central India. It shows that most of river basins have increasing trends both in yearly rainfalls and relative humidity. It considers that the magnitude of increased rainfall for river basins varied is from 2-19% of mean per 100 years. The increase of heavy rain from 9-27 mm per 100 years over different river basins with reduction in the number of rainy days suggest the possibility of increasing intensity of floods. Moreover, it is believed that an increase in areal magnitude of vegetation cover as well as rainfall over the last period has increased the moisture in the atmosphere through enhanced evapotranspiration, which in turn has increased the relative humidity.

Millennial-scale climate variability has been increasingly recognized as one of the most prominent features of the Holocene. However, regional responses, especially in terms of moisture conditions, are poorly documented and understood. Here we present lithologic and magnetic evidence from White Lake in northern New Jersey, USA, to show that low lake levels occurred at about 1.3, 3.0, 4.4 and 6.1 ka (1 ka = 1000 cal. yr BP). The low lake levels are indicated by heterogeneous coarse calcareous sediment layers showing strong magnetic intensities. These detrital layers were likely formed during low stands when shallow-water marls were exposed, oxidized, transported and redeposited. This model is supported by laboratory experiments showing that oxidation of marls can enhance magnetic intensities. The dry periods inferred from the low lake levels of White Lake appear to occur concurrently with the cold periods recorded in the North Atlantic sediments. The correlation between millennial-scale dry/wet cycles inferred from lake-level fluctuations of White Lake and cold/warm cycles in North Atlantic sediments suggests sensitive moisture responses to Holocene millennial-scale climate variability. The dry-cold (or wet-warm) association is supported by instrumental records of the last century showing that the Mid-Atlantic region was dominated by wet conditions, while most parts of the conterminous USA experienced droughts, when the North Atlantic Ocean was warm. The consistent moisture responses of the Mid-Atlantic region to temperature changes of the North Atlantic Ocean may have persisted for the past 6000 years. [ABSTRACT FROM AUTHOR]

A three-dimensional moisture diffusion and volume change model was developed for determining the distribution of soil suction and the associated volume changes in an expansive soil mass under a covered area (e.g., slab foundations or pavements) with respect to time. The model was used to determine a relationship among the edge moisture variation distance, em, the amplitude of surface suction change, U0, and the diffusion coefficient of the soil, α. The edge moisture variation distance calculation is based on the change in soil suction beneath the covered area as a result of climate changes. The edge moisture variation distance is considered to be the distance between the edge of the covered area and the point beneath the covered area where suction change is no more than 0.12 kPa (0.1 pF). Comparison between the predicted values of edge moisture variation distance by using the proposed relationship to that measured in the field or predicted by other methods is also presented. [ABSTRACT FROM AUTHOR]