Temporal observations of surface soil moisture using a passive microwave sensor

1987 ◽  
Vol 21 (3) ◽  
pp. 281-296 ◽  
Author(s):  
T.J. Jackson ◽  
P. O'Neill
Keyword(s):  
Soil Moisture ◽  
Surface Soil ◽  
Passive Microwave ◽  
Surface Soil Moisture ◽  
Microwave Sensor

The Computation of the Effective Temperature of the Land Surface Covered with Canopy

2014 ◽  
Vol 607 ◽  
pp. 830-834
Author(s):  
Hong Zhang Ma ◽  
Su Mei Liu
Keyword(s):  
Soil Moisture ◽  
Brightness Temperature ◽  
Effective Temperature ◽  
Land Surface ◽  
Surface Soil ◽  
Passive Microwave ◽  
Vegetation Canopy ◽  
Surface Soil Moisture ◽  
Remote Sensors ◽  
Energy Exchanges

—Surface soil moisture is an important parameter in describing the water and energy exchanges at the land surface/atmosphere interface. Passive microwave remote sensors have great potential for monitoring surface soil moisture over land surface. The objective of this study is going to establish a model for estimating the effective temperature of land surface covered with vegetation canopy and to investigate how to compute the microwave radiative brightness temperature of land surface covered with vegetation canopy in considering of the canopy scatter effect.

scholarly journals Assimilation of vegetation optical depth retrievals from passive microwave radiometry

2020 ◽  
Vol 24 (7) ◽  
pp. 3431-3450
Author(s):  
Sujay V. Kumar ◽  
Thomas R. Holmes ◽  
Rajat Bindlish ◽  
Richard de Jeu ◽  
Christa Peters-Lidard
Keyword(s):  
Soil Moisture ◽  
Optical Depth ◽  
Optical Sensors ◽  
Land Surface ◽  
Surface Soil ◽  
Land Surface Model ◽  
Weather Conditions ◽  
Passive Microwave ◽  
Surface Model ◽  
Surface Soil Moisture

Abstract. Vegetation optical depth (VOD) retrievals from passive microwave sensors provide analog estimates of above-ground canopy biomass. This study presents the development and analysis of assimilating VOD retrievals from X-, C-, and L-band passive microwave instruments within the Noah-MP land surface model over the Continental U.S. The results from this study demonstrate that the assimilation of VOD retrievals have a significant beneficial impact on the simulation of evapotranspiration and GPP, particularly over the agricultural areas of the U.S. The improvements in the water and carbon fluxes from the assimilation of VOD from X- and C-band sensors are found to be comparable to those obtained from the assimilation of vegetation indices from optical sensors. The study also quantifies the relative and joint impacts of assimilating surface soil moisture and VOD from the Soil Moisture Active Passive (SMAP) mission. The utility of soil moisture assimilation for improving evapotranspiration (ET) is more significant over water-limited regions, whereas VOD DA is more impactful over areas where soil moisture is not the primary controlling factor on ET. The results also indicate that the information on moisture and vegetation states from SMAP can be simultaneously exploited through the joint assimilation of surface soil moisture and VOD. Since passive microwave-based VOD retrievals are available in nearly all weather conditions, their use within data assimilation systems offers the ability to extend and improve the utility obtained from the use of optical/infrared-based vegetation retrievals.

scholarly journals A 1-km daily surface soil moisture dataset of enhanced coverage under all-weather conditions over China in 2003–2019

2022 ◽  
Author(s):  
Peilin Song ◽  
Yongqiang Zhang ◽  
Jianping Guo ◽  
Jiancheng Shi ◽  
Tianjie Zhao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Surface Soil ◽  
Weather Conditions ◽  
Passive Microwave ◽  
Primary Data ◽  
Hydrological Process ◽  
Surface Soil Moisture ◽  
Agricultural Industry ◽  
Quantitative Studies

Abstract. Surface soil moisture (SSM) is crucial for understanding the hydrological process of our earth surface. Passive microwave (PM) technique has long been the primary tool for estimating global SSM from the view of satellite, while the coarse resolution (usually >~10 km) of PM observations hampers its applications at finer scales. Although quantitative studies have been proposed for downscaling satellite PM-based SSM, very few products have been available to public that meet the qualification of 1-km resolution and daily revisit cycles under all-weather conditions. In this study, we developed one such SSM product in China with all these characteristics. The product was generated through downscaling the AMSR-E/AMSR-2 based SSM at 36-km, covering all on-orbit time of the two radiometers during 2003–2019. MODIS optical reflectance data and daily thermal infrared land surface temperature (LST) that had been gap-filled for cloudy conditions were the primary data inputs of the downscaling model, so that the “all-weather” quality was achieved for the 1-km SSM. Daily images from this developed SSM product have quasi-complete coverage over the country during April–September. For other months, the national coverage percentage of the developed product is also greatly improved against the original daily PM observations, through a specifically developed sub-model for filling the gap between seams of neighboring PM swaths during the downscaling procedure. The product is well compared against in situ soil moisture measurements from 2000+ meteorological stations, indicated by station averages of the unbiased RMSD ranging from 0.052 vol/vol to 0.059 vol/vol. Moreover, the evaluation results also show that the developed product outperforms the SMAP-Sentinel (Active-Passive microwave) combined SSM product at 1-km, with a correlation coefficient of 0.55 achieved against that of 0.40 for the latter product. This indicates the new product has great potential to be used for hydrological community, agricultural industry, water resource and environment management.

Exploiting the information in soil moisture and vegetation optical depth retrievals from passive microwave radiometry.

2020 ◽  
Author(s):  
Sujay Kumar ◽  
Thomas Holmes ◽  
Rajat bindlish ◽  
Richard de Jeu ◽  
Christa Peters-Lidard
Keyword(s):  
Soil Moisture ◽  
Optical Depth ◽  
Land Surface ◽  
Surface Soil ◽  
Passive Microwave ◽  
Microwave Radiometry ◽  
Surface Model ◽  
Surface Soil Moisture ◽  
Passive Microwave Radiometry ◽  
The Impact

<p>Historically, microwave radiometry has usually been used for retrieving estimates of soil moisture. As these measurements are also sensitive to vegetation, the attenuation of the microwave signal from vegetation, described by the vegetation optical depth (VOD) parameter can be used an analog of above-ground canopy biomass. This study explores the relative and joint utility of assimilating soil moisture and VOD retrievals from passive microwave radiometry within the NoahMP land surface model. The impact of assimilation on key water and carbon budget terms are quantified through comparisons against reference datasets. The results indicate that the assimilation of soil moisture retrievals has a positive impact on the simulation of surface soil moisture and little impact on evaporative fluxes. In contrast, VOD assimilation has significant impacts on the simulation of vegetation conditions, root zone soil moisture, and evapotranspiration (ET). Over water limited domains with sparse vegetation where soil moisture is the primary control on ET, the assimilation of surface soil moisture is more beneficial than VOD DA. In contrast, over regions with dense vegetation and where water availability is not limiting, transpiration has a significant influence on evapotranspiration. The assimilation of VOD is more beneficial in developing improvements in ET over such areas. The results of this study confirm that soil moisture and VOD retrievals provide independent information that can be jointly exploited through their simultaneous assimilation.</p><p> </p><p> </p>

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