A DUAL‐WAVELENGTH THERMAL INFRARED SCANNER AS A POTENTIAL AIRBORNE GEOPHYSICAL EXPLORATION TOOL

Leonard A. LeSchack; Nancy Kerr Del Grande

doi:10.1190/1.1440682

A DUAL‐WAVELENGTH THERMAL INFRARED SCANNER AS A POTENTIAL AIRBORNE GEOPHYSICAL EXPLORATION TOOL

Geophysics ◽

10.1190/1.1440682 ◽

1976 ◽

Vol 41 (6) ◽

pp. 1318-1336 ◽

Cited By ~ 9

Author(s):

Leonard A. LeSchack ◽

Nancy Kerr Del Grande

Keyword(s):

New York ◽

Soil Moisture ◽

Surface Temperature ◽

Absolute Temperature ◽

Surface Emissivity ◽

Field Site ◽

Ir Radiation ◽

Temperature Variations ◽

Heat Flows ◽

Surface Temperatures

We are investigating a new airborne method for measuring surface temperatures that may be useful for identifying thermal anomalies of geologic origin. From Planck’s equation we derive the valuable approximation that, for small temperature variations, the radiant emittance is proportional to the emissivity times the absolute temperature to the power of (50/wavelength in μm). From this, expressions are obtained for the emitted infrared (ir) radiation measured simultaneously in the 5 and 10 μm bands. Ratios of these expressions are shown to have the following useful properties at 288 K: (a) they are insensitive to surface emissivity variations for vegetated terrain, (b) they vary nearly as the 5th power of the surface temperature, and (c) they distinguish emissivity‐related from temperature‐related effects. We have made preliminary tests of this methodology at a field site in Scipio Center, New York. We have characterized the observed surface temperature variations, the significant effects of soil moisture, and separated out the purely emissivity‐related features of vegetated terrain. Cluster analysis served to divide the ir data into groups that behave similarly as a function of the measured soil moisture. Two such distinct terrain groups were identified at the field site. The ir data were corrected for: (a) natural surface emissivity variations, (b) the intervening atmospheric path, and (c) the reflected sky radiation. The corrected surface temperature data were compared with calculated values computed from a model that simulates the surface temperature, using meteorological, hydrological, topographical, and soil thermal input parameters. The simulated mean surface temperatures, 291.9 K (group 1) and 291.6 K (group 2), differed only by, respectively, 0.0 K and 0.1 K from the measured mean surface temperatures. Our preliminary results suggest the potential for developing a new airborne geophysical method for isolating abnormal heat flows. Weak heat flows, about 10–20 times the terrestrial average, have the effect of raising the surface temperature about 0.1–0.2 K. These temperature anomalies would, with the methodology suggested, appear as a residual difference between the measured (corrected) surface temperature and the simulated surface temperature. Such surface temperature differences appear, from our research, to be measurable by airborne ir scanners when data over surface areas of [Formula: see text] or larger are averaged. Accordingly, our research appears to support the conclusion that surface temperature enhancements of geophysical origin between 0.1 and 0.2 K can be identified using airborne infrared methods.

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Dust Aerosol Optical Depth Retrieval over a Desert Surface Using the SEVIRI Window Channels

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2008jtecha1109.1 ◽

2009 ◽

Vol 26 (4) ◽

pp. 704-718 ◽

Cited By ~ 11

Author(s):

Bart De Paepe ◽

Steven Dewitte

Keyword(s):

Surface Temperature ◽

Aerosol Optical Depth ◽

Optical Depth ◽

Surface Radiation ◽

Retrieval Algorithm ◽

Aerosol Layer ◽

Surface Emissivity ◽

Ir Radiation ◽

Clear Sky ◽

A Minor

Abstract The authors present a new algorithm to retrieve aerosol optical depth (AOD) over a desert using the window channels centered at 8.7, 10.8, and 12.0 μm of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument on board the Meteosat Second Generation satellite. The presence of dust aerosols impacts the longwave outgoing radiation, allowing the aerosols over the desert surfaces to be detected in the thermal infrared (IR) wavelengths. To retrieve the aerosol properties over land, the surface contribution to the satellite radiance measured at the top of the atmosphere has to be taken into account. The surface radiation depends on the surface temperature, which is characterized by a strong diurnal variation over the desert, and the surface emissivity, which is assumed to be constant over a time span of 24 h. The surface emissivity is based on clear-sky observations that are corrected for atmospheric absorption and emission. The clear-sky image is a composite of pixels that is characterized by the highest brightness temperature (BT) of the SEVIRI channel at 10.8 μm, and by a negative BT difference between the channels at 8.7 and 10.8 μm. Because of the lower temperatures of clouds and aerosols compared to clear-sky conditions, the authors assume that the selected pixel values are obtained for a clear-sky day. A forward model is used to simulate the thermal IR radiation transfer in the dust layer. The apparent surface radiation for the three window channels in the presence of aerosols is calculated as a function of the surface emissivity and the surface temperature, the aerosol layer temperature, and the AOD for different aerosol loadings. From these simulations two emissivity ratios, which are stored in lookup tables (LUT), are calculated. The retrieval algorithm consists of processing the clear-sky image and computing the surface emissivity, processing the instantaneous image, and computing the apparent surface radiation for the three window channels. The two emissivity ratios are computed using the radiances at 8.7 and 10.8 μm and at 8.7 and 12.0 μm, respectively. The SEVIRI AOD is obtained by the inversion of these emissivity ratios using the corresponding LUT. The algorithm is applied to a minor dust event over the Sahara between 19 and 22 June 2007. For the validation the SEVIRI AOD is compared with the AOD from the Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) along the satellite track.

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Impacts of Irrigation on Summertime Temperatures in the Pacific Northwest

Earth Interactions ◽

10.1175/ei-d-19-0015.1 ◽

2020 ◽

Vol 24 (1) ◽

pp. 1-26

Author(s):

Patricia M. Lawston ◽

Joseph A. Santanello ◽

Brian Hanson ◽

Kristi Arsensault

Keyword(s):

Remote Sensing ◽

Soil Moisture ◽

Surface Temperature ◽

Land Surface ◽

Maximum Temperature ◽

Daily Maximum Temperature ◽

Climate Signal ◽

Near Surface ◽

Surface Temperatures ◽

Land Surface Temperatures

AbstractIrrigation has the potential to modify local weather and regional climate through a repartitioning of water among the surface, soil, and atmosphere with the potential to drastically change the terrestrial energy budget in agricultural areas. This study uses local observations, satellite remote sensing, and numerical modeling to 1) explore whether irrigation has historically impacted summer maximum temperatures in the Columbia Plateau, 2) characterize the current extent of irrigation impacts to soil moisture (SM) and land surface temperature (LST), and 3) better understand the downstream extent of irrigation’s influence on near-surface temperature, humidity, and boundary layer development. Analysis of historical daily maximum temperature (TMAX) observations showed that the three Global Historical Climate Network (GHCN) sites downwind of Columbia Basin Project (CBP) irrigation experienced statistically significant cooling of the mean summer TMAX by 0.8°–1.6°C in the post-CBP (1968–98) as compared to pre-CBP expansion (1908–38) period, opposite the background climate signal. Remote sensing observations of soil moisture and land surface temperatures in more recent years show wetter soil (~18%–25%) and cooler land surface temperatures over the irrigated areas. Simulations using NASA’s Land Information System (LIS) coupled to the Weather Research and Forecasting (WRF) Model support the historical analysis, confirming that under the most common summer wind flow regime, irrigation cooling can extend as far downwind as the locations of these stations. Taken together, these results suggest that irrigation expansion may have contributed to a reduction in summertime temperatures and heat extremes within and downwind of the CBP area. This supports a regional impact of irrigation across the study area.

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The Western Tibetan Vortex as an emergent feature of near-surface temperature variations

10.5194/egusphere-egu2020-338 ◽

2020 ◽

Author(s):

Remco de Kok ◽

Walter Immerzeel

Keyword(s):

Surface Temperature ◽

20Th Century ◽

Large Scale ◽

High Mountain ◽

Net Radiation ◽

Near Surface ◽

Temperature Variations ◽

Surface Temperatures ◽

Emergent Feature ◽

Main Driver

<p>Glaciers are growing in a part of High Mountain Asia (HMA), contrary to the demise of glaciers worldwide. A proposed explanation for this behaviour is the decreasing strength of the "Western Tibetan Vortex" (WTV), a circular motion of air in the troposphere around northwestern High Mountain Asia, which is proposed to drive near-surface temperatures. Here, we show that the WTV is the change of wind field resulting from changes in near-surface temperature, and that it is not unique to northwestern HMA, but is generally applicable to large parts of the globe. Instead, we argue that net radiation is likely the main driver of near-surface temperatures in Western HMA in summer and autumn, and that the WTV is the response of the atmosphere to changes in temperature. The decreasing strength of the WTV, as seen during summer in the 20th century, is thus likely the result of changing net radiation, and not the main driver of cooling itself. We do argue that the WTV is a useful concept to understand large scale climate variability in the region, and that such an approach could yield important insights in other mid-latitude regions as well.</p>

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Analyzing the Potential Impacts of Soil Moisture on the Observed and Model-Simulated Australian Surface Temperature Variations

Journal of Climate ◽

10.1175/jcli3141.1 ◽

2004 ◽

Vol 17 (21) ◽

pp. 4190-4212 ◽

Cited By ~ 13

Author(s):

Huqiang Zhang

Keyword(s):

Soil Moisture ◽

Climate Variability ◽

Surface Temperature ◽

Soil Water ◽

Land Surface ◽

Water Movement ◽

Water Evaporation ◽

Linear Regression Method ◽

Temperature Variations ◽

Partial Correlations

Abstract Based on observational and modeling analyses, this study aims to assess the potential influence of land surface conditions (soil moisture, in particular) on the Australian surface temperature variations. At first, a simple linear regression method is used to largely remove the ENSO influence from 50-yr observational surface temperature and precipitation datasets. Then, lag and partial correlations of the residuals are analyzed. The impacts of precipitation on the forthcoming surface temperature variations are largely attributed to the soil storage of precipitation water and the slow-varying soil moisture process. Results from partial correlations between precipitation and temperature variations suggest that when responding to anomalous atmospheric forcing, the land surface can introduce some slow-varying processes that can in turn affect the mean state of the atmosphere at monthly or longer scales and increase the predictability of the climate system. Following the observational analysis, results from 16 Atmospheric Model Intercomparison Project Phase 2 (AMIP2) AGCM simulations are analyzed to assess whether land surface modeling can affect the model-simulated climate variability. Lag-correlation analysis reveals that “climatic memory” of soil moisture has different features in the 16 models. Models with simple bucket-type schemes tend to have a rapid decay rate in the retention of soil moisture anomalies and show rapid feedback between land surface and the overlying atmosphere, with a much weaker influence of soil moisture conditions on surface climate variations. In contrast, most models using nonbucket schemes in which more physical processes are introduced in simulating soil water evaporation and soil water movement tend to show slow-varying soil moisture processes, affecting the model integrations at longer time scales. Different characteristics for translating soil moisture memory into climate variability and predictability are seen across the models, and more detailed studies are needed to further explore how land surface processes affect climate variability and predictability.

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Relations between air and surface temperature in discontinuous permafrost terrain near Mayo, Yukon Territory

Canadian Journal of Earth Sciences ◽

10.1139/e04-082 ◽

2004 ◽

Vol 41 (12) ◽

pp. 1437-1451 ◽

Cited By ~ 43

Author(s):

K C Karunaratne ◽

C R Burn

Keyword(s):

Surface Temperature ◽

Ground Surface ◽

Absolute Temperature ◽

Yukon Territory ◽

Near Surface ◽

Ground Temperatures ◽

Surface Temperatures ◽

Air Temperatures ◽

Discontinuous Permafrost ◽

Data Loggers

The association of site characteristics with the n-factor, a ratio of air to ground surface temperature, was investigated at five sites in the boreal forest near Mayo, Yukon Territory. Permafrost was in equilibrium with surface conditions at three sites, was degrading at another, and was absent from the fifth. Air and near-surface ground temperatures were recorded by data loggers between September 2000 and April 2002, and mean daily temperatures were accumulated to calculate n-factors for the freezing (nf) and thawing (nt) seasons. Air temperature did not vary between the sites, so inter-site differences in nf and nt were because of variations in surface temperature. Variations in nf between the sites over the two winters were primarily because of differences in snow depth, but at sites with similar snow cover, the surface temperatures were relatively high when the site was underlain by unfrozen ground. During summer, daily mean surface temperatures were initially less than air temperatures. However, once the thawing front had penetrated below the depth of diurnal temperature fluctuation, the air and ground surface temperatures converged. Since the rate of thaw penetration is governed by soil thermal diffusivity, nt varies directly with this property. These results indicate that subsurface conditions, particularly absolute temperature and ground thermal properties, exert considerable influence on n-factors, and, at the Mayo sites, the influence is greater than that of the vegetation.

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Fine-Scale Urban Heat Patterns in New York City Measured by ASTER Satellite – The Role of Complex Spatial Structures

10.20944/preprints202108.0399.v1 ◽

2021 ◽

Author(s):

Bibhash Nath ◽

Mutlu Ozdogan ◽

Wenge Ni-Meister

Keyword(s):

New York ◽

Land Use ◽

New York City ◽

Surface Temperature ◽

York City ◽

Small Scale ◽

Fine Scale ◽

Spatial Structures ◽

Surface Temperatures ◽

Urban Heat

Urban areas have very complex spatial structures. These spatial structures are primarily composed of a complex network of built environments, which evolve rapidly as the cities expand to meet the growing population’s demand and economic development. Therefore, studying the impact of spatial structures on urban heat patterns is extremely important for sustainable urban planning and growth. We investigated the relationship between surface temperature obtained by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER, at 90 m spatial resolution) on the current EOS-Terra platform and different urban components based on the classification of high-resolution QuickBird imagery. We further investigated the relationships between surface temperature and building footprint and land use information acquired from the New York City (NYC) Department of City Planning. The ASTER image reveals fine-scale urban heat patterns in the NYC metropolitan region. The dark and medium-dark impervious surfaces, along with bright surfaces, generate higher surface temperatures. Even with highly reflective urban materials, the presence of impervious materials leads to an increased surface temperature. At the same time, trees and shadows are effective in reducing urban heat. The data aggregated to the census tract reveals high-temperature clusters in Queens, Brooklyn, and the Bronx region of NYC. These clusters are associated with industrial and manufacturing areas and multi-family walk-up buildings as dominant land use. The census tracts with more trees and higher building height variability generate lower surface temperatures, consistent with shadow cast by high-rise buildings and trees. The results of this study can be valuable for urban heat island modeling on the effects of building heights variability and tree shadows on small-scale surface temperature patterns. It can also help identify the risk areas during extreme heat events to protect public health.

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Application of pyrometer and standard sample to determine surface temperature of studied materials

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2019-12-9-13 ◽

2019 ◽

pp. 9-13

Author(s):

V.Ya. Mendeleyev ◽

V.A. Petrov ◽

A.V. Yashin ◽

A.I. Vangonen ◽

O.K. Taganov

Keyword(s):

Composite Material ◽

Surface Temperature ◽

Relative Error ◽

Wavelength Range ◽

Standard Sample ◽

A Priori ◽

Temperature Changes ◽

Surface Temperatures ◽

Relative Errors ◽

Normal Emissivity

Determining the surface temperature of materials with unknown emissivity is studied. A method for determining the surface temperature using a standard sample of average spectral normal emissivity in the wavelength range of 1,65–1,80 μm and an industrially produced Metis M322 pyrometer operating in the same wavelength range. The surface temperature of studied samples of the composite material and platinum was determined experimentally from the temperature of a standard sample located on the studied surfaces. The relative error in determining the surface temperature of the studied materials, introduced by the proposed method, was calculated taking into account the temperatures of the platinum and the composite material, determined from the temperature of the standard sample located on the studied surfaces, and from the temperature of the studied surfaces in the absence of the standard sample. The relative errors thus obtained did not exceed 1,7 % for the composite material and 0,5% for the platinum at surface temperatures of about 973 K. It was also found that: the inaccuracy of a priori data on the emissivity of the standard sample in the range (–0,01; 0,01) relative to the average emissivity increases the relative error in determining the temperature of the composite material by 0,68 %, and the installation of a standard sample on the studied materials leads to temperature changes on the periphery of the surface not exceeding 0,47 % for composite material and 0,05 % for platinum.

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