Zhengyao Lu
Forskare
Dynamic effect of last glacial maximum ice sheet topography on the east asian summer monsoon
Författare
Summary, in English
The effect of ice sheet topography on the East Asian summer monsoon (EASM) during the Last Glacial Maximum is studied using CCSM3 in a hierarchy of model configurations. It is found that receding ice sheets result in a weakened EASM, with the reduced ice sheet thickness playing a major role. The lower ice sheet topography weakens the EASM through shifting the position of the midlatitude jet, and through altering Northern Hemisphere stationary waves. In the jet shifting mechanism, the lowering of ice sheets shifts the westerly jet northward and decreases the westerly jet over the subtropics in summer, which reduces the advection of dry enthalpy and in turn precipitation over the EASM region. In the stationary wave mechanism, the lowering of ice sheets induces an anomalous stationary wave train along the westerly waveguide that propagates into the EASM region, generating an equivalent-barotropic low response; this leads to reduced lower-tropospheric southerlies, which in turn reduces the dry enthalpy advection into East Asia, and hence the EASM precipitation.
Avdelning/ar
- Institutionen för naturgeografi och ekosystemvetenskap
- MERGE: ModElling the Regional and Global Earth system
- BECC: Biodiversity and Ecosystem services in a Changing Climate
Publiceringsår
2020
Språk
Engelska
Sidor
6929-6944
Publikation/Tidskrift/Serie
Journal of Climate
Volym
33
Issue
16
Dokumenttyp
Artikel i tidskrift
Förlag
American Meteorological Society
Ämne
- Meteorology and Atmospheric Sciences
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0894-8755