Impact of background error statistics on 3D-Var assimilation: case study over the Indian region
IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore
View Archive Info| Field | Value | |
| Relation |
http://cir.csir4pi.in/246/
http://www.springer.com/earth+sciences+and+geography/atmospheric+sciences/journal/703 |
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| Title |
Impact of background error statistics on 3D-Var assimilation:
case study over the Indian region
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| Creator |
V, Rakesh
Goswami, P |
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| Subject |
Climate Modelling
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| Description |
The quality of background error statistics
(BES) is one of the key components for successful
assimilation of observations in a numerical model. Considerable
uncertainties and non-uniqueness exist, however,
in prescribing BES; in particular, the prescription and
impact of BES can also depend on the weather regime and
not much is known in this regard over the Indian region.
We have conducted a series of assimilation experiments
using the WRF three-dimensional variational data assimilation
(3D-Var) system with different BES to asses the
relative improvement in model forecast due to different
BES over the Indian region. The forecasted wind, temperature,
and humidity are verified against NCEP analysis
and conventional radiosondes, while the predicted rainfall
is verified against Tropical Rainfall Measuring Mission
(TRMM) observations. Using a number of parameters to
quantify impact of BES, it is shown that the use of regional
BES (RBES) in WRF 3D-Var significantly improves model
forecast as compared to the control experiment (no
assimilation) and Global BES (GBES). The use of RBES
from National Meteorological Center (NMC) and ensemble
perturbation (ENS) method in WRF 3D-Var produced
similar impact on model forecasts except slight differences
in wind speed. This study highlights the importance
of domain-dependent and region-specific BES in WRF
3D-Var assimilation system; for the selected events, results
obtained using RBES is found to be significantly better
than GBES.
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| Publisher |
SPRINGER
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| Date |
2011-03-13
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Language |
en
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| Rights |
—
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| Identifier |
http://cir.csir4pi.in/246/1/MAP_VR_PG.pdf
V, Rakesh and Goswami, P (2011) Impact of background error statistics on 3D-Var assimilation: case study over the Indian region. Meteorology and Atmospheric Physics, 112 (1-2). pp. 63-79. ISSN ISSN: 0177-7971 (print version) ISSN: 1436-5065 (electronic version) |
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