Doug Rickman

Using Remote Sensing Data to Evaluate Surface Soil Properties in Alabama Ultisols

Evaluation of surface soil properties via remote sensing could facilitate soil survey mapping, erosion prediction, and allocation of agrochemicals for precision management. The objective of this study was to evaluate the relationship between soil spectral signature and surface soil properties in conventionally managed row crop systems. High-resolution remote sensing data were acquired over bare fields in the Coastal Plain, Appalachian Plateau, and Ridge and Valley provinces of Alabama using the Airborne Terrestrial Applications Sensor multispectral scanner. Soils ranged from sandy Kandiudults to fine textured Rhodudults. Surface soil samples (0 to 1 cm) were collected from 161 sampling points for gravimetric soil water content, soil organic carbon, particle size distribution, and citrate dithionite extractable iron content. Surface roughness and crusting were also measured during sampling. Two methods of analysis were evaluated: (1)multiple linear regression using common spectral band ratios and (2)partial least-squares regression. Our data show that thermal infrared spectra are highly, linearly related to soil organic carbon, sand and clay content. Soil organic carbon content was the most difficult to quantify in these highly weathered systems, where soil organic carbon was generally <1.2%. Estimates of sand and clay content were best using partial least-squares regression at the Valley site, explaining 42 to 59% of the variability. In the Coastal Plain, sandy surfaces prone to crusting limited estimates of sand and clay content via partial least-squares and regression with common band ratios. Estimates of iron oxide content were a function of mineralogy and best accomplished using specific band ratios, with regression explaining 36 to 65% of the variability at the Valley and Coastal Plain sites, respectively.

Functional Comparison of Lunar Regoliths and Their Simulants

AbstractLunar regolith simulants are essential to the development of technology for human exploration of the Moon. Any equipment that will interact with the surface environment must be tested with simulant to mitigate various risks, such as unexpected mechanical abrasion, chemical interactions, or thermal failures. To reduce the greatest amount of risk, the simulant must replicate the lunar surface as well as possible. To quantify the similarities and differences between simulants, the figure of merit (FOM) was developed. The Figure of Merit software compares the simulants and regolith by particle size, particle shape, density, and the relative abundance of minerals, rocks, and glass; these four properties dictate the majority of the remaining characteristics of geologic material. As a result, not only is the risk made quantifiable, but a conceptual framework is established for the evaluation of simulants. There are important limitations in our knowledge and technology pertaining to simulants. Specific ex...

Thermal Properties of Lunar Regolith Simulants

Various high temperature chemical processes have been developed to extract oxygen and metals from lunar regolith. These processes are tested using terrestrial analogues of the regolith. But all practical terrestrial analogs contain H2O and/or OH(-), the presence of which has substantial impact on important system behaviors. We have undertaken studies of lunar regolith simulants to determine the limits of the simulants to validate key components for human survivability during sustained presence on the moon. Differential Thermal Analysis (DTA) yields information on phase transitions and melting temperatures. Themo-Gravimetric Analysis (TGA) with mass spectrometric (MS) determination of evolved gas species yields chemical information on various oxygenated volatiles (water, carbon dioxide, sulfur oxides, nitrogen oxides and phosphorus oxides) and their evolution temperature profiles. The DTA and TGAMS studies included JSC-1A fine, NU-LHT-2M and its proposed feed stocks: anorthosite; dunite; HQ (high quality) glass and the norite from which HQ glass is produced. Fig 1 is a data profile for anorthosite. The DTA (Fig 1a) indicates exothermic transitions at 355 and 490 C and endothermic transitions at 970 and 1235 C. Below the 355 C transition, water (Molecular Weight, MW, 18 in Fig 1c) is lost accounting for approximately 0.1% mass loss due to water removal (Fig 1b). Just above 490 C a second type of water is lost, presumably bound in lattices of secondary minerals. Between 490 and the 970 transition other volatile oxides are lost including those of hydrogen (third water type), carbon (MW = 44), sulfur (MW = 64 and 80), nitrogen (MW 30 and 46) and possibly phosphorus (MW = 79, 95 or 142). Peaks at MW = 35 and 19 may be attributable to loss of chlorine and fluorine respectively. Negative peaks in the NO (MW = 30) and oxygen (MW = 32) MS profiles may indicate the production of NO2 (MW = 46). Because so many compounds are volatilized in this temperature range quantification of the mass loss associated with individual species is difficult. Similar information will be presented for the other materials studied in this investigation.

Evaluating Corn Nitrogen Variability via Remote-Sensed Data

Abstract Transformations and losses of nitrogen (N) throughout the growing season can be costly. Methods in place to improve N management and to facilitate split N applications during the growing season can be time consuming and logistically difficult. Remote sensing (RS) may be a method to rapidly assess temporal changes in crop N status and to promote more efficient N management. This study was designed to evaluate the ability of three different RS platforms to predict N variability in corn (Zea mays L.) leaves during vegetative and early reproductive growth stages. Plots (15 × 15 m) were established in the Coastal Plain (CP) and in the Appalachian Plateau (AP) physiographic regions each spring from 2000 to 2002 in a completely randomized design. Treatments consisted of four N rates (0, 56, 112, and 168 kg N ha−1) applied as ammonium nitrate (NH4NO3) replicated four times. Spectral measurements were acquired via spectroradiometer (λ = 350–1050 nm), Airborne Terrestrial Applications Sensor (ATLAS) (λ = 400–12,500 nm), and the IKONOS satellite (λ = 450–900 nm). Spectroradiometer data were collected on a biweekly basis from V4 through R1. Due to the nature of satellite and aircraft acquisitions, these data were acquired per availability. Chlorophyll meter (SPAD) and tissue N were collected as ancillary data, along with each RS acquisition. Results showed vegetation indices derived from hand-held spectroradiometer measurements as early as V6–V8 were linearly related to yield and tissue N concentration. The ATLAS data were correlated with tissue N at the AP site during the V6 stage (r 2 = 0.66), but no significant relationships were observed at the CP site. No significant relationships were observed between plant N and IKONOS imagery. By using a combination of the greenness vegetation index and the normalized difference vegetation index, RS data acquired via ATLAS and the spectroradiometer could be used to evaluate tissue N variability and to estimate corn yield variability given ideal growing conditions.

A Quantitative Method for Evaluating Regolith Simulants

The surface of rocky planets, moons and some other astronomical bodies have significant amounts of broken geologic materials. In the absence of more specific, applicable terminology, such material is generically termed regolith. Even on relatively simple bodies, like the Moon, the nature of the regolith is fairly complex. For mission development a regolith needs to be simulated; and many have been created for the Moon and Mars. But there is no generally accepted method to express the quality of a simulant. This paper proposes a method for ascertaining the quality of a simulant through the use of Figures‐of‐Merit. In support of NASA’s exploration mission this method has been implemented. MSFC has creating a suite of simulants whose compositions cover the samples returned by the Apollo missions. These are termed Standard Lunar Regolith Simulant (SLRS) materials. The approach is adaptable, extensible and evolutionary. It is considered highly applicable to other regoliths of interest.

The use of the Airborne Thermal/Visible Land Application Sensor (ATLAS) to Determine the Thermal Response Numbers for Urban Areas.

The additional heating of the air over the city is the result of the replacement of naturally vegetated surfaces with those composed of asphalt, concrete, rooftops and other man-made materials. The temperatures of these artificial surfaces can be 20 to 40degC higher than vegetated surfaces. This produces a dome of elevated air temperatures 5 to 8degC greater over the city, compared to the air temperatures over adjacent rural areas. Urban landscapes are a complex mixture of vegetated and non vegetated surfaces. It is difficult to take enough temperature measurements over a large city area to characterize the complexity of urban radiant surface temperature variability. The NASA Airborne Thermal and Land Applications Sensor (ATLAS) operates in the visual and IR bands was used in February 2004 to collect data from San Juan, Puerto Rico with the main objective of investigating the Urban Heat Island (UHI) in tropical cities. Ref. [1] developed the TRN (thermal response number) as a technique using aircraft remotely sensed surface temperatures to quantify the thermal response of urban surfaces. The TRN was used to quantify the thermal response of various urban surface types ranging from completely vegetated surfaces to asphalt pavements for San Juan, Puerto Rico.