I'm using precipitation cal dataset of Half hourly 0.1 deg gridded GPM IMERG late run product over Hilly region. Problem is Precipitation values measured with ground station falling on the particular grid of daily frequency shows lesser rates compared with GPM late run product for a specific timescale of 10 days. I want to know the accuracy evaluated with ground station data of frequent intervals nearing/equal to half hourly IMERG product in mountainous terrain. Please suggest me where I would get the information regarding my querry.
Dear Arun,
I think your question is very sophisticate and need to be answered by right person. I did couple of training on GPM IMERGE data and know the right person who can give you right answer.
Please send your question to Dr. Goorge Huffman, GPM Deputy Project Scientist, NASA Goddard Space Flight Center or Dr. Dalia Kirschbaum, Deputy Project Scientist for Application. Their mail address are [email protected] and [email protected], respectively.
I hope this helps, but please let me know if you need anything else or if you have any other questions.
Thanks
Thank you soo much for your information. G S Huffman Sir Has earlier responded my querry, I'm following him in Researchgate. I ll take note of mail address and mail my querry.
Thank you.
Hello Arun.
Yes, this question is not an easy one. What I mean is that the product is relatively knew and validation exercises are ongoing all over the world. In a while the first results will be published by several of us and we will know more.
I think that not even my good friend George Huffman is able to fully answer the question because of what is mentioned above.
IPWG will surely conduct soon a validation campaign:
http://ipwg.isac.cnr.it/
However, for the time being I would refer to the technical documentation available at:
http://pmm.nasa.gov/data-access/downloads/gpm
(go to Level 3 and you will find IMERG).
I know this is not quite satisfactory, but more will come soon.
Cheers
Sir,
Thank you so much for letting me know about the workshop related to my querry.
Actually we are also validating with certain ground stations of Daily frequency.
Overall we could find little over estimation in GPM late run products. I hope this product is pretty much reliable for assessing extreme events like Chennai Floods caused during November, December 2015.
I mailed my query to George Huffman sir, one of his colleagues Mr. Jacksan Tan have addressed my querry validating with hourly frequency ground station data. That was much useful.
He was also insisting to use Version 4 yet to be released would be final calibrated and better than this.
Thank you.
A very fist comparison in Italy, at daily time scale, between GPM late run and ground-based observations (period March-December 2015).
The figure shows the 1-day correlation map.
Cheers, L
...and here it is by merging IMERG late run with SM2RAIN-ASCAT (http://dx.doi.org/10.13140/RG.2.1.4068.6481/1 and http://dx.doi.org/10.13140/RG.2.1.4434.8563)
Luca Sir,
Thanks, you have shown some interesting validations. Some of the pixels having R = 0.1 to 0.4 are improved in your final product. It seems using ASCAT product have some significance in removing the error in GPM product. If you have some published article related to this work please do share. It seems very interesting.
Take a look to the following study by Omranian and Sharif:
Evaluation of the Global Precipitation Measurement (GPM) Satellite Rainfall Products Over the Lower Colorado River Basin, Texas
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