Source apportionment of atmospheric water over East Asia – a source tracer study in CAM5.1
The atmospheric water tracer (AWT) method is implemented in the Community Atmosphere Model version 5.1 (CAM5.1) to quantitatively identify the contributions of various source regions to precipitation and water vapour over East Asia. Compared to other source apportionment methods, the AWT method was...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-02-01
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| Series: | Geoscientific Model Development |
| Online Access: | http://www.geosci-model-dev.net/10/673/2017/gmd-10-673-2017.pdf |
| Summary: | The atmospheric water tracer (AWT) method is implemented in the Community
Atmosphere Model version 5.1 (CAM5.1) to quantitatively identify the
contributions of various source regions to precipitation and water vapour
over East Asia. Compared to other source apportionment methods, the AWT
method was developed based on detailed physical parameterisations, and can
therefore trace the behaviour of atmospheric water substances directly and
exactly. According to the simulation, the northern Indian Ocean (NIO) is the
dominant oceanic moisture source region for precipitation over the Yangtze
River valley (YRV) and southern China (SCN) in summer, while the north-western
Pacific (NWP) dominates during other seasons. Evaporation over the South
China Sea (SCS) is responsible for only 2.7–3.7 % of summer
precipitation over the YRV and SCN. In addition, the Indo-China Peninsula is
an important terrestrial moisture source region (annual contribution of
∼ 10 %). The overall relative contribution of each source region to
the water vapour amount is similar to the corresponding contribution to
precipitation over the YRV and SCN. A case study for the SCS shows that only
a small part ( ≤ 5.5 %) of water vapour originates from local
evaporation, whereas much more water vapour is supplied by the NWP and NIO. In
addition, because evaporation from the SCS represents only a small
contribution to the water vapour over the YRV and SCN in summer, the SCS
mainly acts as a water vapour transport pathway where moisture from the NIO
and NWP meet. |
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| ISSN: | 1991-959X 1991-9603 |