We hypothesize that the strong sensitivity of radar backscatter to surface dielectric properties, and hence to the phase (solid or liquid) of any water near the surface, should make space-borne radar observations a powerful tool for large-scale spatial monitoring of the freeze/thaw state of the land surface, and thus ecosystem growing season length.

NSCAT remote sensing radar BOREAS freeze thaw grow↗

NASA NTRS1998

In Vivo Dieletric Response as Related to Tissue Structure, Function and Physiologic Activity in Selected Trees

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vegetated terrain Physiologic Activity Vivo Dielet↗

NASA NTRS1998

An All Solid-State 640 GHz Subharmonic Mixer

This paper reports on the first all solid-state two-diode subharmonically pumped (SHP) mixer operating at 640 GHz.

subharmonically pumped (SHP) antiparallel pair↗

NASA NTRS1997

NSCAT Observation of Spring Thaw in Alaskan Boreal Forest

The focus of this effort is the assessment of spaceborne scatteromter observations for monitoring landscape freeze/thaw transitions in the boreal forest thereby providing a means for estimating growing season duration.

Spring thaw Alaskan boreal forest NSCAT temperatur↗

NASA NTRS1997

Automated Instrumentation for Continuous Monitoring of the Dielectric Properties of Woody Vegetation: System Design, Implementation and Selected In Situ Measurements

Design and implementation of a system for the automated and continous in situ monitoring of the dielectric constant of woody vegetation tissue is presented.

dielectric properties woody vegetation↗

NASA NTRS1996

Diurnal and spatial variation of xylem flow and xylem dielectric constant in conifers

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diurnal variation spatial variation xylem flow xyl↗

NASA NTRS1994

Remote Sensing of Tropical Forests with Multi-Frequency Polarimetric Radar (AIRSAR) as an Aid in Vegetation Classification

Vegetation maps of inaccessible areas in the tropics tend to divide vegetation into broad types.

vegetation maps backscatter polarization↗

NASA NTRS1994

Water Relations of Two Neotropical Rainforest Types in the Lowlands of the Amazon Basin at Rio Manu, Peru

Two major forest types in the upper Amazonian headwater region are floodplain and upland (terra firme) forests.

Amazonian headwater floodplain and upland forests ↗

NASA NTRS1994

Diurnal and Seasonal Trends in Canopy Transpiration and Conductance of Pristine Forest Types in Belize, Central America

Five semi-deciduous broadleaf forest types growing over tropical karst in Belize, Central America, were monitored for three years to study diurnal and seasonal changes of transpiration and micro-meteorologic conditions.

semi-deciduous drought vapor pressure gradient xer↗

NASA NTRS1994

Microclimate, Water Potential, Transpiration, and Bole Dielectric Constant of Coniferous and Deciduous Tree Species in the Continental Boreal Ecotone of Central Alaska

Tree canopy microclimate, xylem water flux and xylem dielectric constant have been monitored in situ since June 1993 in two adjacent natural forest stands in central Alaska. The deciduous stand represents a mature balsam poplar site on the Tanana River floodplain, while the coniferous stand consists of mature white spruce with some black spruce mixed in. During solstice in June and later in summer, diurnal changes of xylem water potential were measured to investigate the occurrence and magnitude of tree transpiration and dielectric constant changes in stems.

bole dielectric constant coniferous trees deciduou↗

NASA NTRS1994

Characterization of Canopy Physiology at Boreas with SAR

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BOREAS boreal forest biome atmosphere Canada Princ↗

NASA NTRS1994

Characterization of Canopy Physiology at Boreas with SAR

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atmosphere Canada Saskatchewan↗