Skip header and navigation

2 records – page 1 of 1.

Evaporative cooling over the Tibetan Plateau induced by vegetation growth.

https://arctichealth.org/en/permalink/ahliterature264529
Source
Proc Natl Acad Sci U S A. 2015 Jul 13;
Publication Type
Article
Date
Jul-13-2015
Author
Miaogen Shen
Shilong Piao
Su-Jong Jeong
Liming Zhou
Zhenzhong Zeng
Philippe Ciais
Deliang Chen
Mengtian Huang
Chun-Sil Jin
Laurent Z X Li
Yue Li
Ranga B Myneni
Kun Yang
Gengxin Zhang
Yangjian Zhang
Tandong Yao
Source
Proc Natl Acad Sci U S A. 2015 Jul 13;
Date
Jul-13-2015
Language
English
Publication Type
Article
Abstract
In the Arctic, climate warming enhances vegetation activity by extending the length of the growing season and intensifying maximum rates of productivity. In turn, increased vegetation productivity reduces albedo, which causes a positive feedback on temperature. Over the Tibetan Plateau (TP), regional vegetation greening has also been observed in response to recent warming. Here, we show that in contrast to arctic regions, increased growing season vegetation activity over the TP may have attenuated surface warming. This negative feedback on growing season vegetation temperature is attributed to enhanced evapotranspiration (ET). The extra energy available at the surface, which results from lower albedo, is efficiently dissipated by evaporative cooling. The net effect is a decrease in daily maximum temperature and the diurnal temperature range, which is supported by statistical analyses of in situ observations and by decomposition of the surface energy budget. A daytime cooling effect from increased vegetation activity is also modeled from a set of regional weather research and forecasting (WRF) mesoscale model simulations, but with a magnitude smaller than observed, likely because the WRF model simulates a weaker ET enhancement. Our results suggest that actions to restore native grasslands in degraded areas, roughly one-third of the plateau, will both facilitate a sustainable ecological development in this region and have local climate cobenefits. More accurate simulations of the biophysical coupling between the land surface and the atmosphere are needed to help understand regional climate change over the TP, and possible larger scale feedbacks between climate in the TP and the Asian monsoon system.
PubMed ID
26170316 View in PubMed
Less detail

Extensive fires in southeastern Siberian permafrost linked to preceding Arctic Oscillation.

https://arctichealth.org/en/permalink/ahliterature307310
Source
Sci Adv. 2020 01; 6(2):eaax3308
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
01-2020
Author
Jin-Soo Kim
Jong-Seong Kug
Su-Jong Jeong
Hotaek Park
Gabriela Schaepman-Strub
Author Affiliation
School of GeoSciences, University of Edinburgh, Edinburgh, UK.
Source
Sci Adv. 2020 01; 6(2):eaax3308
Date
01-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Abstract
Carbon release through boreal fires could considerably accelerate Arctic warming; however, boreal fire occurrence mechanisms and dynamics remain largely unknown. Here, we analyze fire activity and relevant large-scale atmospheric conditions over southeastern Siberia, which has the largest burned area fraction in the circumboreal and high-level carbon emissions due to high-density peatlands. It is found that the annual burned area increased when a positive Arctic Oscillation (AO) takes place in early months of the year, despite peak fire season occurring 1 to 2 months later. A local high-pressure system linked to the AO drives a high-temperature anomaly in late winter, causing premature snowmelt. This causes earlier ground surface exposure and drier ground in spring due to enhanced evaporation, promoting fire spreading. Recently, southeastern Siberia has experienced warming and snow retreat; therefore, southeastern Siberia requires appropriate fire management strategies to prevent massive carbon release and accelerated global warming.
PubMed ID
31934623 View in PubMed
Less detail