Geoscience Reference
In-Depth Information
Figure 9.18.
Mean snow water equivalent (mm) for March from six atmospheric
reanalysis: MERRA, ERA-I, ASR, NARR (the North American Regional Reanalysis),
JRA-25 (the Japanese twenty-five-year reanalysis), and CFSR (courtesy of D. Slater,
NSIDC, Boulder, CO). (See plate section for color version.)
Examples of modern atmospheric reanalyses include:
Modern Era Retrospective-Analysis for Research and Applications
(MERRA):
This reanalysis was developed by the National Aeronautics and
Space Administration (NASA) for the satellite era (1979 onward) (Rienecker
et al.,
2011
). MERRA uses the Goddard Earth Observing System Data
Assimilation System Version 5. The analysis is performed at a horizontal res-
olution of 2/3 degree longitude by 1/2 degree latitude at seventy-two vertical
levels. Surface data, near surface meteorology, selected upper-air fields and
vertically integrated fluxes and budgets are produced at one hour intervals.
NOAA Climate Forecast System Reanalysis (CFSR):
The CFSR (Saha et al.,
2010
) also extends from 1979 onward. The global atmosphere resolution is
about 38 km with sixty-four levels in the vertical. The atmospheric model
includes observed variations in carbon dioxide along with changes in aerosols
and other trace gases and solar variations. Oceanic and land surface output
products are available at a horizontal resolution of 0.33° latitude × 0.33° longi-
tude and on an hourly basis.
ERA-Interim:
This is an effort by ECMWF to prepare for their next general
reanalysis that will replace the discontinued ERA-40 system (Dee et al.,
2011
).
ERA-Interim data are also available from 1979 onward. Compared to ERA-
