Doubled CO2 precipitation changes for the Susquehanna Basin: down-scaling from the Genesis general circulation model
✍ Scribed by Robert G. Crane; Bruce C. Hewitson
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 412 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0899-8418
No coin nor oath required. For personal study only.
✦ Synopsis
Arti®cial neural nets are used in an empirical down-scaling procedure to derive daily subgrid-scale precipitation from general circulation model (GCM) geopotential height and speci®c humidity data. The neural net-based transfer functions are developed using a 2 62Á5 gridded data assimilation product from the Goddard Space Flight Center, applied to a 464 matrix of grid-cells centred on the Susquehanna river basin. The down-scaled precipitation is a close match to the observed data (temporal correlations at individual grid-points range from 0Á6 to 0Á84). Doubled CO 2 climate change scenarios are produced by applying the same transfer functions to the geopotential height and speci®c humidity ®elds from 16CO 2 and 26CO 2 simulations of version II of the GENESIS climate model. The analysis indicates a 32 per cent increase in spring and summer rainfall over the basin, resulting from changes in both moisture availability and the orientation of the storm track over the region. The down-scaled precipitation increases, derived from the change in the GCM's circulation and humidity ®elds, are considerably larger than the change in the model's actual computed precipitation.