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How to quantify GRACE uncertainty?

PostPosted: Thu Jan 23, 2020 1:33 pm
by walterchandler
I'm looking for a way to quantify the uncertainty associated with GRACE equivalent water thickness measurements for a specific region. The region I'm working with has an area of about 11,500 km^2, which I know is quite small of an area to be using GRACE data for, but it is currently my only option. It is also my understanding that errors and uncertainties are larger at small spatial scales, compared to larger scales.

Is it possible to quantify what the associated uncertainties in this case might be? I'm using the average of the JPL and CSR monthly EWT values as is suggested in this article: https://grace.jpl.nasa.gov/data/choosing-a-solution/

Any help is appriciated. Thank you.

Re: How to quantify GRACE uncertainty?

PostPosted: Mon Jan 27, 2020 11:26 am
by wenhaoli
Hi,

Sorry for the delay. I Have forwarded your inquiry to GRACE/GRACE-FO Science Team. They will provide the feedback soon.

I will post the their response once I receive it.

Thanks,

Re: How to quantify GRACE uncertainty?

PostPosted: Sun Apr 26, 2020 2:22 pm
by assilina
Hi,

Scale factors, measurement and leakage errors were shared in the previous release (Level 3, RL-05). However, these are not available in the current GRACE and GRACE-FO datasets. Has any information been shared on how to calculate the uncertainty in the TWS data?

Thanks a lot.

Re: How to quantify GRACE uncertainty?

PostPosted: Tue Apr 28, 2020 8:36 am
by podaac
Thank you for your inquiry.

Your request has been forwarded to the GRACE science team for further assistance.

We will get back to you as soon as possible.

Thank you for your patience.

Re: How to quantify GRACE uncertainty?

PostPosted: Wed May 20, 2020 5:18 pm
by wenhaoli
Hi,

I have just got the feedback from GRACE-FO Level-3 product team about the Level-3 products and its scale-factor data. Following is their formal statement.

"For the most accurate and up-to-date analysis of land and ice water storage we recommend to use JPL’s Mascon solution (https://grace.jpl.nasa.gov/data/get-dat ... l_mascons/). These data have been processed to minimize measurement errors, feature the best signal-to-noise ratio, and contain monthly error estimates. The JPL mascon data can also be explored interactively via JPL’s Data Analysis Tool (https://grace.jpl.nasa.gov/data-analysis-tool). The scale factors for the LND products (based on JPL, CSR, GFZ conventional spherical harmonic GRACE/GRACE-FO gravity fields) are in the process of being updated."

Please let's know if you have more questions.

Thanks for your patience.