Does summer precipitation trend over and around the Tibetan Plateau depend on elevation?

Abstract

The Tibetan Plateau (TP) experienced a rapid warming and wetting in recent decades. The elevation dependence of warming rate has been established, while the question of trend in precipitation against the elevation gradient remains open. By using the in situ observation of precipitation, air temperature, and surface specific humidity from 91 stations over and around the TP, this study investigated how the trends in summer precipitation varied along the elevation gradient over and around the TP during the period 1970–2014. The major findings are as follows: (1) the trends in summer precipitation from 1970 to 2014 displayed an increasing tendency at a rate of 0.83% decade−1 km−1 with the increased elevation, and the rate for 1991–2014 (2.23% decade−1 km−1) is even greater and (2) the temporal trends in surface air temperature, surface specific humidity (surface water vapour) from in situ observations and total column of water vapour from Japanese 55‐year reanalysis (JRA‐55) data over most stations consistently display similar elevation dependence, which provides a plausible explanation for the elevation dependence of the summer precipitation trends based on the Clausius–Clapeyron relationship. The large‐scale atmospheric circulations are other possible factors influencing the elevation dependence of summer precipitation trends, which needs further investigations.

Climatic and associated cryospheric, biospheric, and hydrological changes on the Tibetan Plateau: a review

“…The majority of the stations in semi‐arid and humid‐zones of central TP shows increasing precipitation trends, while at the periphery, decreasing trends have been observed. Summer precipitation increased with elevation (1000–4500 m) over TP from 1970 to 2014 at a rate of 0.83% decade −1 km −1 (Li et al ., ). The moisture transports from the west by westerlies and from the southwest by the Indian summer monsoon likely contributed the most to the precipitation over the TP (Zhang et al ., ).…”

“…This is greater than the rate in Northern Hemisphere (0.38 °C decade −1 ) and almost 1.5 times the rate of global warming (0.32 °C decade −1 ) (Zhang et al ., ). Recent studies (Liu et al ., ; Qin et al ., ; Pepin, ; Guo et al ., , ; Li et al ., ) have reported that the changing trends in air temperature, wind speed, and summer precipitation are elevation‐dependent in the TP and its surroundings. Because of its high sensitivity to climate change, TP changes are considered as an indicator of global warming effects (Yao et al ., ).…”

Observed changes in temperature extremes over China–Pakistan Economic Corridor during 1980–2016

“…In recent years, EDW becomes an interesting area of research for understanding the climate change phenomenon. Related studies revealed that warming at higher altitudes is more obvious than that at lower altitudes (You et al, 2010;Guo et al, 2016a;Li et al, 2017;Sun et al, 2017;You et al, 2017). However, many studies have also stated that there are no clear evidence of EDW phenomenon (You et al, 2008).…”

Precipitation changes in the Qilian Mountains associated with the shifts of regional atmospheric water vapour during 1960–2014

“…In JJA and SON, precipitation increase is still the largest for QM_3km, followed by that for QM < 2 km, and is the least for QM_2km. The results imply that the precipitation wetting becomes more pronounced at higher elevations than at lower elevations in the QM from 1960 to 2014 as warmer air in mountain regions can hold more moisture according to the Clausius–Clapeyron relationship (Wentz et al, ; Trenberth, ; Li et al, ). The increasing trends for precipitation in DJF and MAM are more obvious at elevations of QM_2km than at other elevations, which show no strict elevation dependency of precipitation increasing trends.…”

“…Reanalysis data sets are the results of data assimilation making use of a background model forecast together with applicable observations, including their number and type (Wang and Zeng, ; You et al, ). These components, the model physical parameterizations, as well as satellite data processing are responsible for part of the uncertainties (Bosilovich et al, ; Ma et al, ; Li et al, ). Spurious variations in reanalysis data sets suffer from discontinuities in radiosonde observations, even for the modern satellite era from 1979 to present when satellite observations play an ever‐increasingly important role in restraining upper atmosphere (Zhao et al, ).…”