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| Titel |
Diurnal and seasonal variation of vertical velocity pattern in boundary layer over a high altitude site in central Himalayan region |
| VerfasserIn |
Krishna Kumar Shukla, D. V. Phanikumar, Rob K. Newsom, K. Niranjan Kumar, V. R. Kotamarthi |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101082
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| Publikation (Nr.) |
 EGU/EGU2015-147.pdf |
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| Zusammenfassung |
| During the Indo-US collaborative Ganges Valley Aerosol Experiment (GVAX) a
Doppler lidar (DL) was operated continuously from June 2011 to March 2012 at
a high altitude site on Manora Peak (29.4o N; 79.2o E; 1958 m above mean sea
level (amsl)) in the the Himalayan foothills. The lidar provided height-resolved
measurements of vertical velocity and attenuated backscatter above the site. This
study investigates seasonal and diurnal variations of vertical velocity and attenuated
backscatter in the local boundary layer height ~1 km above ground level (agl) during the
monsoon(June-August) ,post-monsoon (September-November), winter (December-February)
and premonsoon (March) periods. The upslope flows were observed during the
daytime and down slope flows were are observed during the nighttime. The magnitude
of the vertical velocity varied between 0.1-0.4 m.s-1 in all seasons. The vertical
velocity variances ranged from 0.2 to 1.5 m-2s-2. Variances were higher during the
daytime due to convection. At night, the variance decreased due to cooling at the
surface. There is good correlation (R2 ~ 0.26, 0.66 and 0.4) between the daily
mean attenuated backscatter and relative humidity during post-monsoon, winter and
pre-monsoon seasons respectively and an anti-correlation (R2 ~0.03) between the
attenuated backscatter and relative humidity in monsoon season. There are very less
co-relation (R2 ~0.06, 0.19, 0.002 and 0.12) between daily mean vertical velocity and
attenuated backscatter in all the seasons respectively. The mean diurnal vertical
velocity component is modulated by the terdiurnal (8-hour) component in all the
seasons. We investigate the impact of variable weather conditions on vertical velocity. |
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