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As reported in previous studies, global warming has caused a clear uptick in dryland areas since the 1950s. Meanwhile, the accelerated expansion of drylands has become particularly evident over the past 40 years, with dry/wet patterns showing significant differences prior to and after 1980. This paper uses the Precipitation/Potential evaporation (P/PET) index to analyze changes occurring in the dry/wet structure of various spatial and temporal scales during 1948–2008. The results show the emergence of complex aridity changes on a regional scale. While aridity generally decreased in the drylands of Asia during 1948–2008, the change in aridity was opposite in the drylands of the American and African continents between 1948 and 1979 and 1980–2008. Specifically, drylands in the American continent showed a wetting tendency during 1948–1979 and a drying tendency during 1980–2008, whereas drylands in the African continent underwent significant drying during 1948–1979 followed by subtle wetting in 1980–2008. Even though rapid warming since the 1980s has become an increasingly important cause of the recent global drying trend, especially in East and Central Asia, the changes in aridity in the American and African drylands is attributable to natural variabilities in precipitation associated with multi-decadal surface sea temperature changes, along with large-scale circulation patterns. • Dry/wet patterns in dryland areas show significant differences in the decades prior to and after 1980. • The change in aridity was opposite in American and African drylands between 1948–1979 and 1980–2008. • Aridity changes in American and African drylands are closely related to multi-decadal changes in surface sea temperature. [ABSTRACT FROM AUTHOR]

Climate on the Tibetan Plateau is often considered sensitive to global changes, yet the degree of sensitivity in different spaces and seasons prior to instrumental records is not clear. In this paper, we studied tree-ring maximum latewood density (MXD) to examine the late-summer (August–September) temperature variation over the past two and half centuries on the eastern Tibetan Plateau. The MXD regional chronology was established from 109 tree-ring samples of Balfour spruce [ Picea likiangensis var. balfouriana (Rehd. et Wils.)] at four high elevation sites. The chronology exhibited a high correlation ( r = 0.82, n = 56, p < 0.001) with the mean August–September temperature. Using the tree-ring data, we reconstructed the late-summer temperature for the period A.D. 1765–2009. The reconstruction accounted for 71.4% of the variance in instrumental temperature in the period 1954–2009. The reconstructed temperature did not show a warming trend in the past 250 years, suggesting a unique characteristic of late-summer temperature variability in the study region of the Tibetan Plateau. Our tree-ring data are useful for further understanding of the plateau's thermal condition in late summer and its role in regulating southward retreat of the Southwest Asian monsoon. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the long-term trends in surface temperature in several large Asian cities (Seoul, Tokyo, Osaka, Taipei, Manila, Bangkok, and Jakarta) have been analyzed for estimating the effects of urban warming. A new index, E-HII, is proposed: it is the value obtained by subtracting the temperature data of the four grids around the city from the observational temperature data in the city. Osaka shows the largest E-HII, increasing from approximately 2.4 °C in 1901 to almost 3 °C after 1981. The E-HIIs of Seoul, Tokyo, and Taipei, have increased by 1 °C to 2 °C. Jakarta and Bangkok exhibited a lower E-HII. E-HIIs of Manila and Bangkok have been increasing rapidly after 1961. [Copyright &y& Elsevier]