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New Updates/Changes to GLOBE/SMAP Block Soil Moisture Protocol

Jan 20, 2016

SMAP Satellite Mission

There have been some exciting changes to the SMAP Block Pattern Soil Moisture Protocol. These changes will aid in the understanding of our planet’s soil moisture – and make your data collection easier.

When you are entering the SMAP Block Pattern data on the Live Data Entry system, you will now be able to choose the “Soil State” as:
Measurable: You can successfully collect the soil sample. (Collect Your Sample)
Frozen ground: You cannot collect the soil sample because the temperature of the soil has caused it to freeze. (Do Not Collect Your Sample)
Snow on ground: There is snow cover on your sample site. (Do Not Collect Your Sample)
Graupel on ground: There is graupel on your sample site. Graupel is soft hail or snow pellets. (Do Not Collect Your Sample)
Hail on ground: There is hail on your sample site. Hail are irregular lumps of ice, often called hailstones. (Do Not Collect Your Sample)
Frozen water on ground: The soil has been saturated and the water on top of your sample site is frozen. (Do Not Collect Your Sample)
If you select any of the last 5 choices, a dialog box will prompt you to make any comments and submit your reason (Soil State) for not collecting the sample. This information is vital data to the SMAP mission. The radiometer onboard the satellite can determine whether or not the soil is frozen based on the microwave signal received. With the addition of your data, the satellite data can be validated.

When soil is less dense than water, volumetric soil moisture can easily exceed the .55 ml/ml value. Because of this, the data entry validity test for volumetric soil moisture from 0.55 ml/ml to 0.7 ml/ml has been changed, so that reports of these conditions will be accepted as accurate.

The next step is that we will be eliminating the need to have a sample bulk density measurement the first time you enter SMAP data. Converting soil moisture from gravimetric to volumetric is needed because SMAP measures the volume of water in the surface soil layer. The sample bulk density is used to make this conversion. Until there is a sample bulk density measurement for a site, the conversion cannot be made and the data cannot be compared to SMAP observations. The requirement is to have at least one sample bulk density measurement in every 10 soil moisture measurements. When the fix is made, data will be accepted for days before the sample bulk density is supplied and the conversion to volumetric soil moisture values will be made. In any case, your soil moisture measurements are valuable, so please save them to a paper data sheet until the system is fixed to accept them.

You can visit the GLOBE/SMAP Soil Moisture Measurement Field Campaign web pages to follow all of the current campaign information and updates -- including past webinars, blogs, and everything you need to know about collecting soil moisture measurements using the SMAP Block Pattern Soil Moisture Protocol, as well as view the protocol instructional video.

The next webinar will be held on 2 February 2016 (4 p.m. ET/9 p.m. UTC): “1 Year of the SMAP Mission and Global Shout-Outs to all the GLOBE schools/teams collecting SMAP soil moisture data." The webinar link is: https://gsfc610.adobeconnect.com/globesmap/

Read the campaign-related blogs at: http://www.globe.gov/web/smap/overview/blog-posts. If you would like to guest blog about your SMAP protocol measurement experience, please contact Brian Campbell, Senior NASA Earth Flight Science Education and Communication Specialist at brian.a.campbell@nasa.gov.