Atlantic and Southern Oscillations as seen in a satellite precipitation dataset and in models
Precipitation is a parameter that varies on many different spatial and temporal scales. Here we look at interannual variations associated with the North Atlantic Oscillation (NAO) and the Southern Oscillation (SO), comparing the spatial and temporal changes as shown by three datasets. The GPCP produ...
| Main Authors: | , , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.482.5335 http://www.noc.soton.ac.uk/JRD/SAT/pers/gdq_others/Kyte_et_al_JGR_14pp.pdf |
| Summary: | Precipitation is a parameter that varies on many different spatial and temporal scales. Here we look at interannual variations associated with the North Atlantic Oscillation (NAO) and the Southern Oscillation (SO), comparing the spatial and temporal changes as shown by three datasets. The GPCP product is based upon satellite data, whereas both the NCEP and ECMWF climatologies are produced through reanalysis of atmospheric circulation models. All three products show a consistent response to the NAO in the North Atlantic region, with negative states of the NAO corresponding to increases in precipitation over Greenland and Southern Europe, but to a decrease over Northern Europe. None of the climatologies display any net change in total rainfall as a result of the NAO, but rather a redistribution of precipitation patterns. However, this redistribution of rain is important because of its potential effect on oceanic overturning circulation. Similarly, all three datasets concur that the SO has a major effect on precipitation in certain tropical regions; however, there is some disagreement amongst the datasets as to the regional sensitivity, with NCEP showing a much weaker response than GPCP and ECMWF over Indonesia. The GPCP and NCEP climatologies show that the various phases of El Niño and La Niña act to redistribute, rather than enhance, the freshwater cycle. Given that the models incorporate no actual observations of rain, and are known to be imperfect, it is surprising how well they represent these interannual phenomena. 1. |
|---|