Back to Search
Start Over
Ensemble transform sensitivity method for adaptive observations
- Source :
- Advances in Atmospheric Sciences; January 2016, Vol. 33 Issue: 1 p10-20, 11p
- Publication Year :
- 2016
-
Abstract
- The Ensemble Transform (ET) method has been shown to be useful in providing guidance for adaptive observation deployment. It predicts forecast error variance reduction for each possible deployment using its corresponding transformation matrix in an ensemble subspace. In this paper, a new ET-based sensitivity (ETS) method, which calculates the gradient of forecast error variance reduction in terms of analysis error variance reduction, is proposed to specify regions for possible adaptive observations. ETS is a first order approximation of the ET; it requires just one calculation of a transformation matrix, increasing computational efficiency (60%–80% reduction in computational cost). An explicit mathematical formulation of the ETS gradient is derived and described. Both the ET and ETS methods are applied to the Hurricane Irene (2011) case and a heavy rainfall case for comparison. The numerical results imply that the sensitive areas estimated by the ETS and ET are similar. However, ETS is much more efficient, particularly when the resolution is higher and the number of ensemble members is larger.
Details
- Language :
- English
- ISSN :
- 02561530 and 18619533
- Volume :
- 33
- Issue :
- 1
- Database :
- Supplemental Index
- Journal :
- Advances in Atmospheric Sciences
- Publication Type :
- Periodical
- Accession number :
- ejs37330036
- Full Text :
- https://doi.org/10.1007/s00376-015-5031-9