Evaluation of Short-Range Forecasts from a Mesoscale Model Over the Indian Region During Monsoon 2006
IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore
View Archive Info| Field | Value | |
| Title |
Evaluation of Short-Range Forecasts from a Mesoscale Model Over the Indian Region
During Monsoon 2006
|
|
| Creator |
V, Rakesh
|
|
| Subject |
Climate Modelling
Indian Monsoon Meteorology and Climatology |
|
| Description |
This study examines the short-range forecast accuracy
of the Pennsylvania State University-National Center for
Atmospheric Research Mesoscale Model (MM5) as applied to the
July 2006 episode of the Indian summer monsoon (ISM) and the
model’s sensitivity to the choice of different cumulus parameterization
schemes (CPSs), namely Betts-Miller, Grell (GR) and
Kain-Fritsch (KF). The results showed that MM5 day 1 (0–24 h
prediction) and day 2 (24–48 h prediction) forecasts using all three
CPSs overpredicted monsoon rainfall over the Indian landmass,
with the larger overprediction seen in the day 2 forecasts. Among
the CPSs, the rainfall distribution over the Indian landmass was
better simulated in forecasts using the KF scheme. The KF scheme
showed better skill in predicting the area of rainfall for most of the
rainfall thresholds. The root mean square error (RMSE) in day 1 and
day 2 rainfall forecasts using different CPSs showed that rainfall
simulated using the KF scheme agreed better with the observed
rainfall. As compared to other CPSs, simulation using the GR
scheme showed larger RMSE in wind speed prediction at 850 and
200 hPa over the Indian landmass. MM5 24-h temperature forecasts
at 850 hPa with all the CPSs showed a warm bias of the order of 1 K
over the Indian landmass and the bias doubled in 48-h model
forecasts. The mean error in temperature prediction at 850 hPa over
the Indian region using the KF scheme was comparatively smaller
for all the forecast intervals. The model with all the CPSs overpredicted
humidity at 850 hPa. The improved prediction by MM5
with the KF scheme is well complemented by the smaller error
shown by the KF scheme in vertical distribution of heat and mean
moist static energy in the lower troposphere. In this study, the KF
scheme which explicitly resolve the downdrafts in the cloud column
tended to produce more realistic precipitation forecasts as compared
to other schemes which did not explicitly incorporate downdraft
effects. This is an important result especially given that the area
covered by monsoon-precipitating systems is largely from stratiform-
type clouds which are associated with strong downdrafts in the
lower levels. This result is useful for improving the treatment of
cumulus convection in numerical models over the ISM region.
|
|
| Publisher |
Springer
|
|
| Date |
2010-06-23
|
|
| Type |
Article
PeerReviewed |
|
| Format |
application/pdf
|
|
| Identifier |
http://cir.cmmacs.ernet.in/82/1/pageoph_new.pdf
V, Rakesh (2010) Evaluation of Short-Range Forecasts from a Mesoscale Model Over the Indian Region During Monsoon 2006. Pure and Applied Geophysics. ISSN 0033-4553 (print version) |
|
| Relation |
http://www.springerlink.com
http://cir.cmmacs.ernet.in/82/ |
|