IEEE Geoscience and Remote Sensing Magazine - December 2023 - 161

constant, and soil temperature were obtained. Vegetation
samples were collected from 50 cm × 50 cm quadrants.
Gravimetric analysis was conducted on all soil and vegetation
samples to obtain soil and vegetation water content,
respectively. Jeffrey Walker and Binayak Mohanty helped
the participants with insights into the planning and execution
of the SM field campaigns.
Later in the day, there were lectures on radar remote sensing
of SM by Paul Siqueira and Seungbum Kim [Figure 6(a)
and (b)]. Paul Siqueira introduced the radar equation, the
nature of targets, and the measurements obtained from
Synthetic Aperture Radar (SAR) sensors. He later discussed
various scattering mechanisms as the radar signals interact
with targets. He concluded by discussing the lift-mounted
L-band radar available at the University of Florida. He demonstrated
how the backscatter varies with changing SM and
vegetation properties for corn and soybean crops. Seungbum
Kim discussed physics-based backscattering models
using soil and vegetation information, including the role
of surface roughness and various scattering phenomena.
Later, he discussed several retrieval algorithms and the
associated challenges while estimating SM from SAR
observations. Hands-on sessions by Narendra Das and
Seungbum Kim followed these sessions [Figure 6(d)].
Narendra Das taught how to obtain SMAP data from the
National Snow and Ice Data Center repository. He provided
hands-on exercises to access and visualize SMAP-Sentinel
1 km SM data, explaining the quality flags associated with
SM products. He also showed how other variables, such as
the brightness temperature and vegetation optical depth,
could be accessed from HDF files. Seungbum Kim discussed
processing raw SAR data from Sentinel-1 using IDL
and the Sentinel Application Platform software.
The following lecture by Subimal Ghosh provided insights
into the role of SM in land-atmosphere interactions
and providing climate services in India [Figure 6(c)]. He discussed
the variability of monsoons and extremes in India
in the lecture and talked about the role of the land surface
in monsoon precipitation through recycled precipitation
and incorporating irrigation signals in the land feedback
mechanism. In the context of climate services, he presented
the utility of SM and weather forecasts for irrigation water
management. He concluded the lecture with an introduction
to a Living Lab set up in Satara district, Maharashtra,
India. The Satara Living Lab is intended to measure SM and
other hydroclimatic variables for agriculture water management
and understand human-nature interactions.
SUMMARY OF ACTIVITIES ON THE THIRD DAY OF THE
SECOND INTERNATIONAL SOIL MOISTURE SCHOOL
The third day started with a lecture by Narendra Das on the
synergy between active and passive microwave sensors for
high-resolution SM retrievals [Figure 7(a)]. In this lecture, he
presented the theory of integrating passive and active microwave
observations. It involves downscaling vertically polarized
brightness temperatures using SAR measurements and
retrieving SM from downscaled brightness temperatures using
RTMs. He explained the operational SMAP-Sentinel-1
(a)
(b)
(c)
(a)
(b)
(c)
(d)
(e)
(d)
FIGURE 6. The lectures by (a) Paul Siqueira, (b) Seungbum Kim,
and (c) Subimal Ghosh. (d) The hands-on session by Narendra Das
and Seungbum Kim.
DECEMBER 2023 IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE
FIGURE 7. The lectures by (a) Narendra Das, (b) Seungbum Kim,
(c) Binayak Mohanty, (d) Prashant Srivastava, and (e) Sat Kumar
Tomer. (f) The briefing on the IEEE Bombay Chapter GRSS section
by Gulab Singh.
161
(f)
IEEE Geoscience and Remote Sensing Magazine - December 2023

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