Korean RAR
Comparisons of rainrates from IMERG (V06B) and Korean RAD-RAR
IMERG
Integrated Multi-Satellite Retrievals for GPM (IMERG) Algorithm
is intended to intercalibrate, merge, and interpolate "all" satellite microwave precipitation estimates,
together with microwave-calibrated infrared (IR) satellite estimates, precipitation gauge analyses, and
potentially other precipitation estimators at fine time and space scales for the TRMM and GPM eras over
the entire globe. The system is run several times for each observation time, first giving a quick estimate
and successively providing better estimates as more data arrive. The final step uses monthly gauge data
to create research-level products. Background information and references are provided to describe the context
and the relation to other similar missions. Issues involved in understanding the accuracies obtained from
the calculations are discussed. Throughout, a baseline Day-1 product is described, together with options
and planned improvements that might be instituted before or after launch depending on maturity and
project constraints.
The IMERG gridded estimates are on a 30-minute temporal resolution and
a 0.1o by 0.1o spatial resolution
extending from 180W to 180E and 90S to 90N (for Version 5 and later; 60S
to 60N for Version 4 and earlier ).
For more information about IMERG,
read IMERG_ATBD_V06.3.pdf
Thanks to George Huffman and David T. Bolvin for providing IMERG Early-Run, Late-Run, and Final-Run products.
Korean RAD-RAR
Korea Meteorological Administration(KMA) has developed a Real-time ADjusted Radar-AWS
(Automatic Weather Station) Rainrate (RAD-RAR) system using eleven
radars over South Korea.
The Korean RAD-RAR data are on a 1-hour temporal resolution and a 1-km by 1-km spatial resolution
extending from 119.883E to 136.316E and 29.1906N to 45.7572N.
Thanks to Geunhyoerk Ryu at KMA for providing Korean RAD-RAR data for this study.
Comparisons between IMERG and Korean RAD-RAR (or called Korean QPE)
The comparisons are conducted over the area (125E-129.5E, 34N-38N)
during Mar 2014- May 2019 between Korean
QPE and Version-06B IMERG (Early, Late and Final Runs).
As the server disk space is full, validations for other versions of
IMERG products are removed from this server.
- Area-averaged daily rainfall
All data (rain and no rain) from each product at its native resolution
(QPE: 1km, 1h; IMERG: 0.1o, 0.5h)
are accumulated to daily rainfall, and averaged over the land,
ocean, or entire area. Click here for the
Land/Ocean mask.
The daily rainfall cutoff time is 00Z.
- Scatter plot for area-averaged hourly rainrates
- Density plot for 0.1o hourly rainrates
- Density plot for 0.1o hourly rainrates by IMERG_Final sources
- PDF plot for 0.1o hourly rain occurrence and
volume with different rain thresholds
The number listed in the upper left panel is the total
rain occurrence in all bins for each product.
- PDF plot for 0.1o hourly rain occurrence and
volume by IMERG_Final sources
- Error component plot for 0.1o hourly rainrates
Rain/no-rain threshold is set to 0.1 mm/h.
- Hourly rainrate [mm/h] contours at 0.1oresolutions
Hourly rainrate for each product is accumulated from its native temporal resolutions (1h for QPE, 0.5h for IMERG)
at 0.1o spatial resolution. QPE data are resampled to
0.1o for easy comparison with IMERG.
0- and non-0 rain rates are all included.
- Daily rainfall [mm] contours at 0.1o resolutions
Daily rainfall for each product is accumulated from its native temporal resolutions (1h for QPE, 0.5h for IMERG)
at 0.1o spatial resolution. QPE data are resampled to
0.1o for easy comparison with IMERG.
0- and non-0 rain rates are all included.
The daily rainfall cutoff time is 00Z.
- Monthly, seasonal, yearly rainfall [mm/day] contours at 0.1o resolutions
Monthly, seasonal, or yearly rainfall for each product is accumulated from its daily rainfall.
- Mission-to-date (Mar 2014 - May 2019) rainfall [mm/day] contours at 0.1o resolutions
Mission-to-date rainfall for each product is averaged from its monthly rainfall.
- Time series of bias and correlation for sensor/method consistency
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