Updated Aug 2017
- Rapid Refresh and HRRR specification of sea- and lake-surface temperature and snow/ice
both use the same external SST/ice data fields,
but interpolated to higher resolution, of course, in the 3km HRRR.
- Starting with HRRRv2, snow and soil fields in HRRR are cycled at 3km,
independent from the RAP fields.
- For HRRRv1, HRRR SST/LST/snow/ice fields
were copied from coarser 13km RAP grid.
- Starting with HRRRv3/RAPv4, 15" MODIS land-use data is introduced,
which gives finer resolution of inland lakes and coastlines
than the previous 30" data.
Water-surface temperature (ocean and lakes)
Other than lake-surface-temperature exceptions below starting in 2013-14, specified using
Lake-surface-temperature exceptions implemented
with RAPv2 implementation at NCEP - 25 Feb 2014, or starting late Sept 2013 for ESRL experimental RAP)
Snow geographic cover (and 2-layer snow water equivalent and snow temperature) is cycled in the Rapid Refresh
on an ongoing basis, since 2011 at this point. The NESDIS IMS snow cover is used to horizontally trim
and build snow cover, as described below.
NESDIS IMS snow cover
Applied to RAP at ~0z each day after new IMS snow data available.
Trim snow cover at all points where shown by IMS-snow field
Build snow cover (starting in 2013) (snow water equivalent based on snow at neighbor points or = 1mm if neighbors are snow-free) where needed.
- Starting in summer 2017, RTG_SST_HR was used for all
lake surface temperatures (as well as for all water surface temperatures).
- Before this change (ESRL RAP/HRRR on 13 June 2017, NCEP-oper RAP/HRRR on 12 July 2017),
NAM_SST was used for inland lakes other than Great Lakes, specified using
N.American SST (NAM_SST) - 14km resolution
With improvements made to RTG_SST_HR in Nov 2016, it was found
that it gave superior small lake temperatures than NAM_SST,
which was far too cold in spring 2017.
Grids available here:
- Great Salt Lake, Salton Sea, Lake Champlain - use monthly climatology - also introduced to RAP with RAPv2
- Before these dates, RAP used RTG_SST_HR for LST for all lakes
(Back to RAP homepage)
Prepared by Stan Benjamin
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