Title: Aridity changes in the Tibetan Plateau in a warming climate

Abstract

Desertification in the Tibetan Plateau (TP) has drawn increasing attention in the recent decades. It has been postulated as a consequence of climate aridity due to the observed warming. This study quantifies the aridity changes in the TP and attributes the changes to different climatic factors. Using the ratio of P/PET (precipitation to potential evapotranspiration) as an aridity index to indicate changes in dryness and wetness in a given area, P/PET was calculated using observed records at 83 stations in the TP, with PET calculated using the Penman–Monteith (PM) algorithm. Spatial and temporal changes of P/PET in 1979-2011 are analyzed. Results show that stations located in the arid and semi-arid northwestern TP are becoming significantly wetter and stations in the semi-humid southeastern TP are becoming drier, though not significantly, in the recent three decades. The aridity change patterns are significantly correlated with precipitation, sunshine duration and diurnal temperature range changes at confidence level of 99.9% from two-tail t-test. Temporal correlations also confirm the significant correlation between aridity changes with the three variables, with precipitation being the most dominant driver of P/PET changes at interannual time scale. PET changes are insignificant but negatively correlated with P/PET in the cold season. Inmore » the warm season, however, correlation between PET changes and P/PET changes are significant at confidence level of 99.9% when the cryosphere melts near the surface. Significant correlation between wind speed changes and aridity changes occurs in limited locations and months. Consistency in the climatology pattern and linear trends in surface air temperature and precipitation calculated using station data, gridded data, and nearest grid-to-stations for the TP average and across sub-basins indicate the robustness of the trends despite the large spatial heterogeneity in the TP that challenge climate monitoring.« less

Authors:

Gao, Yanhong; Li, Xia; Leung, Lai-Yung R.; Chen, Deliang; Xu, Jianwei

Publication Date:

Tue Mar 10 00:00:00 EDT 2015

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Atmospheric Science and Global Change Div. (ASGC)

Sponsoring Org.:

USDOE

OSTI Identifier:

1182877

Report Number(s):

PNNL-SA-106739
Journal ID: ISSN 1748-9326; KP1703010

Grant/Contract Number:  

2013CB956004; 41322033; AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Environmental Research Letters

Additional Journal Information:

Journal Volume: 10; Journal Issue: 3; Journal ID: ISSN 1748-9326

Publisher:

IOP Publishing

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; desertification, aridity, Tibetan Plateau