Towards a better monitoring of soil moisture using a combination of estimates from passive microwave and thermal observations

Zulamet Vega-Martínez, Marouane Temimi, Martha C. Anderson, Christopher Hain, Nir Krakauer, Robert Rabin, Reza Khanbilvardi

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Soil moisture is a key variable in hydrological and meteorological processes. It exhibits significant temporal and spatial variation. Therefore, the use of satellite imagery to monitor its variability is crucial. The main objective of this work is to implement a multi-satellite approach which combines soil moisture estimates from passive microwave and thermal observations to improve the monitoring of soil wetness on a continental scale. Soil moisture estimates are obtained from passive microwave data from the AMSR-E NASA product and from thermal and near infrared observations using the ALEXI model. Ultimately, a statistical combination of these two products would overcome their individual limitations, allowing for better monitoring of soil moisture. The main limitation of passive microwave-based products is their coarse spatial resolution. Their main advantage, however, is their capability to penetrate clouds. On the other hand, the main advantage of the ALEXI-based product is its higher spatial resolution and deeper sampling into the root zone. Cloud blockage is its main limitation. The prospective product, the result of the combination, would have a better spatial resolution than the passive microwave-based product and a better temporal coverage than the ALEXI-based product. Several locations with different land cover conditions were chosen to compare and analyse the difference between the two products. These areas are located in Washington State, California, Texas, Alabama, Florida and New York, USA. The Atmosphere-Land Exchange (ALEXI) model mainly uses GOES data to calculate soil moisture in clear-sky days on a continental scale. On cloudy days, when visual imagery is affected by clouds, a gap-filling technique is adopted to continue inferring soil moisture. A preliminary visualization of the soil moisture products from ALEXI and AMSR-E has been conducted, including daily evaluations for the different combinations of data in different regions. A reasonable agreement has been noticed between the two products. The consistency between the two products suggests that they can be combined for better monitoring of soil wetness.

Original languageEnglish
Title of host publicationRemote Sensing and Hydrology
Pages42-45
Number of pages4
StatePublished - 2012
EventRemote Sensing and Hydrology Symposium - Jackson Hole, WY, United States
Duration: 27 Sep 201030 Sep 2010

Publication series

NameIAHS-AISH Publication
Volume352
ISSN (Print)0144-7815

Conference

ConferenceRemote Sensing and Hydrology Symposium
Country/TerritoryUnited States
CityJackson Hole, WY
Period27/09/1030/09/10

Keywords

  • ALEXI
  • AMSR-E
  • Evapotranspiration
  • Passive microwave
  • Soil moisture

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