Remote sensing of vegetation water content using shortwave infrared reflectances

Date

2007-12-01

Author

Hunt Jr., E. Raymond
Yılmaz, Mustafa Tuğrul

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Vegetation water content is an important biophysical parameter for estimation of soil moisture from microwave radiometers. One of the objectives of the Soil Moisture Experiments in 2004 (SMEX04) and 2005 (SMEX05) were to develop and test algorithms for a vegetation water content data product using shortwave infrared reflectances. SMEX04 studied native vegetation in Arizona, USA, and Sonora, Mexico, while SMEX05 studied corn and soybean in Iowa, USA. The normalized difference infrared index (NDII) is defined as (R-850 - R-1650)/(R-800 + R-1650), where R-850 is the reflectance in the near infrared and R1650 is the reflectance in the shortwave infrared. Simulations using the Scattering by Arbitrarily Inclined Leaves (SAIL) model indicated that NDII is sensitive to surface moisture content. From Landsat 5 Thematic Mapper and other imagery, NDII is linear with respect to foliar water content with R-2 = 0.81. The regression standard error of the y estimate is 0.094 mm, which is equivalent to about a leaf area index of 0.5 in m(2) m(-2). Based on modeling the dynamic water flow through plants, the requirement for detection of water stress is about 0.01 mm, so detection of water stress may not be possible. However, this standard error is accurate for input into the tau-omega model for soil moisture. Therefore, NDII may be a robust backup algorithm for MODIS as a standard data product.

Subject Keywords

Normalized difference infrared index, Equivalent water thickness, SAIL model, Plant water stress, Soil moisture experiments, MODIS

URI

https://hdl.handle.net/11511/40112

DOI

https://doi.org/10.1117/12.734730

Conference Name

Conference on Remote Sensing and Modelling of Ecosystems for Sustainability IV

Collections

Department of Civil Engineering, Conference / Seminar

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Remote sensing of leaf equivalent water thickness and vegetation water content using shortwave infrared reflectances Hunt, Er; Yılmaz, Mustafa Tuğrul; Jackson, Tj (null; 2008-04-28) Vegetation water content is an important biophysical parameter for estimation of soil moisture from microwave radiometers. One of the objectives of the Soil Moisture Experiments in 2004 (SMEX04) and 2005 (SMEX05) were to develop and test algorithms for a vegetation water content data product using shortwave infrared reflectances. SMEX04 studied native vegetation in Arizona, USA, and Sonora, Mexico, while SMEX05 studied corn and soybean in Iowa, USA. The normalized difference infrared index (NDII) is defined...
Remote sensing of vegetation water content from equivalent water thickness using satellite imagery Yılmaz, Mustafa Tuğrul; Jackson, Thomas J. (Elsevier BV, 2008-05-15) Vegetation water content (VWC) is one of the most important parameters for the successful retrieval of soil moisture content from microwave data. Normalized Difference Infrared Index (NDII) is a widely-used index to remotely sense Equivalent Water Thickness (EWT) of leaves and canopies; however, the amount of water in the foliage is a small part of total VWC. Sites of corn (Zea mays), soybean (Glycine max), and deciduous hardwood woodlands were sampled to estimate EWT and VWC during the Soil Moisture Experi...
Comparison of vegetation water contents derived from shortwave-infrared and passive-microwave sensors over central Iowa Hunt, E. Raymond; Li, Li; Yılmaz, Mustafa Tuğrul; Jackson, Thomas J. (2011-09-15) Retrieval of soil moisture content using the vertical and horizontal polarizations of multiple frequency bands on microwave sensors can provide an estimate of vegetation water content (VWC). Another approach is to use foliar-water indices based on the absorption at shortwave-infrared wavelengths by liquid water in the leaves to determine canopy water content, which is then related to VWC. An example of these indices is the normalized difference infrared index (NDII), which was found to be linearly related t...
Remote sensing of canopy water content during SMEX'04 and SMEX'05 using shortwave-infrared reflectances Hunt Jr., E. Raymond; Yılmaz, Mustafa Tuğrul; Jackson, Thomas J. (2008-12-01) The Soil Moisture Experiments in 2004 and 2005 were conducted to validate algorithms for soil moisture retrievals. One of the key parameters for determination of soil moisture from microwave sensors is the vegetation water content of canopy and stems. We tested if canopy water content could be determined from reflectances in the shortwave-infrared and if the amount of canopy water content was related to the total vegetation water content by allometric equations. The normalized difference infrared index (NDI...
Comparison of vegetation water content estimates from WindSat and MODIS Hunt Jr., E. Raymond; Li, Li; Yılmaz, Mustafa Tuğrul; Jackson, Thomas J. (2010-12-01) Retrieval of soil moisture content from microwave sensors also returns an estimate of vegetation water content. Remotely sensed indices from optical sensors can be used to estimate canopy water content. For corn and soybean in central Iowa, there are allometric relationships between canopy water content and vegetation water content. The Normalized Difference Infrared Index from MODIS was used to estimate vegetation water content. We compared independent estimates of vegetation water content from WindSat and...

Citation Formats

E. R. Hunt Jr. and M. T. Yılmaz, “Remote sensing of vegetation water content using shortwave infrared reflectances,” San Antonio, CA, 2007, vol. 6679, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40112.