scholarly journals Angular Dependence and Spatial Distribution of Jupiter's Centimeter‐Wave Thermal Emission From Juno's Microwave Radiometer

2020 ◽  
Vol 7 (11) ◽  
Author(s):  
Fabiano Oyafuso ◽  
Steven Levin ◽  
Glenn Orton ◽  
Shannon T. Brown ◽  
Virgil Adumitroaie ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Angular Dependence ◽  
Thermal Emission ◽  
Microwave Radiometer ◽  
Centimeter Wave

scholarly journals Ground-based remote sensing of thin clouds in the Arctic

2012 ◽  
Vol 5 (6) ◽  
pp. 8653-8699 ◽  
Author(s):  
T. J. Garrett ◽  
C. Zhao
Keyword(s):  
Water Vapor ◽  
Thermal Emission ◽  
Stratospheric Ozone ◽  
Microwave Radiometer ◽  
Single Layer ◽  
Primary Source ◽  
The Arctic ◽  
Liquid Water Path ◽  
Water Path ◽  
Microphysical Properties

Abstract. This paper describes a method for using interferometer measurements of downwelling thermal radiation to retrieve the properties of single-layer clouds. Cloud phase is determined from ratios of thermal emission in three "micro-windows" where absorption by water vapor is particularly small. Cloud microphysical and optical properties are retrieved from thermal emission in two micro-windows, constrained by the transmission through clouds of stratospheric ozone emission. Assuming a cloud does not approximate a blackbody, the estimated 95% confidence retrieval errors in effective radius, visible optical depth, number concentration, and water path are, respectively, 10%, 20%, 38% (55% for ice crystals), and 16%. Applied to data from the Atmospheric Radiation Measurement program (ARM) North Slope of Alaska – Adjacent Arctic Ocean (NSA-AAO) site near Barrow, Alaska, retrievals show general agreement with ground-based microwave radiometer measurements of liquid water path. Compared to other retrieval methods, advantages of this technique include its ability to characterize thin clouds year round, that water vapor is not a primary source of retrieval error, and that the retrievals of microphysical properties are only weakly sensitive to retrieved cloud phase. The primary limitation is the inapplicability to thicker clouds that radiate as blackbodies.

scholarly journals AGB circumstellar envelopes: molecular observations

1999 ◽  
Vol 191 ◽  
pp. 363-372
Author(s):  
V. Bujarrabal
Keyword(s):  
Spatial Distribution ◽  
Chemical Reactions ◽  
Flux Distribution ◽  
Thermal Emission ◽  
Data Interpretation ◽  
Gas Content ◽  
Agb Stars ◽  
Empirical Knowledge ◽  
Circumstellar Envelopes ◽  
Molecular Line

Due to the low excitation requirements and easy observation from the ground, molecular line observations probably constitute our main source of empirical knowledge on circumstellar envelopes (CSEs) around AGB stars. The CO rotational transitions, the most intense ‘thermal’ lines, are efficiently used to determine the total gas content and its spatial distribution in wide samples of objects. Thermal emission from other molecules is mainly useful in order to study their abundances and the chemical reactions taking place in CSEs. Maser lines are easily observed due to their high intensity and the flux distribution in very compact spatial spots and narrow profile spikes, characteristic of the exponential amplification; however the data interpretation is difficult due to the intricate pumping processes. The most important maser lines (of SiO, H2O and OH) arise from very different regions, which allows the study of various components of the CSEs. We will focus here on SiO masers.

Anisotropic Polarized Emission of a Doped Silicon Lamellar Grating

2006 ◽  
Vol 129 (1) ◽  
pp. 11-16 ◽  
Author(s):  
F. Marquier ◽  
M. Laroche ◽  
R. Carminati ◽  
J.-J. Greffet
Keyword(s):  
Surface Plasmons ◽  
Angular Dependence ◽  
Thermal Emission ◽  
Azimuthal Angle ◽  
Radiative Cooling ◽  
Polarized Emission ◽  
Doped Silicon ◽  
Resonant Emission ◽  
Thermal Sources ◽  
Total Hemispherical Emissivity

Thermal emission of a doped silicon grating has been studied in the plane perpendicular to the grooves. We show how the excitation of surface plasmons produce a resonant emission weakly depending on the polarization and azimuthal angle. We analyze in detail the polarization and angular dependence of the emission out of the plane perpendicular to the grooves. Two kinds of thermal sources, directional and quasi-isotropic, are studied. They have been designed in a previous paper. We also compute the total hemispherical emissivity of these gratings. In addition we show that in applications such as radiative cooling, these sources are less efficient than other structures.

scholarly journals Spatial Distribution of Rainfall with Elevation in Satluj River Basin: 1986-2010, Himachal Pradesh, India

2015 ◽  
Vol 57 ◽  
pp. 163-175 ◽  
Author(s):  
Sandeep Kumar ◽  
Santosh
Keyword(s):  
Spatial Distribution ◽  
River Basin ◽  
Thermal Emission ◽  
Spline Interpolation ◽  
Temporal Distribution ◽  
Geographical Information ◽  
Maximum Rainfall ◽  
Orographic Effects ◽  
Mountainous Regions ◽  
Satluj River

The complex relationship between topography and precipitation in mountainous regions such as Himalayas is evident from the pattern of rainfall distribution. The variation in precipitation with altitude is controlled by mean height of clouds and decrease in water vapours with altitude. Spatially distributed measurements of precipitation have gained renewed interest in connection with climate change impact studies. Precipitation values are usually available from a limited number of gauge stations and their spatial estimates can be obtained by interpolation techniques such as Inverse Distance Weighted (IDW), Kriging and Spline. In the present study, precipitation-elevation relationship can be established using Digital Elevation Model (DEM) (Advanced Spaceborne Thermal Emission and Reflection Radiometer-ASTER, 30m resolution), Spline interpolation technique in Geographical Information System (GIS) environment and point data from various gauge stations spread over the Satluj River Basin. Changes of spatial distribution of precipitation with elevation show a distinct shift. Bhakra Dam (5854.60 mm) to Rampur (4451.10 mm), there is continuous variation in rainfall with increase in altitude. But beyond Rampur, variation is very high. Swarghat shows exceptional rainfall (8031.76 mm), may be due to position of mountains and their orographic effects. Maximum rainfall was observed in the lower Himalayas i.e. Shiwalik range. Negligible rainfall was observed beyond Kaza (470 mm), above the elevation of around 3756 m. The general trend of rainfall exhibits that the lower and middle parts experience good rainfall whereas the upper part experiences less rainfall. Such spatial and temporal distribution of rainfall with elevation provides an important platform for hydrologic analysis, planning and management of water resources.

scholarly journals Analysis of Saturn’s thermal emission at 2.2-cm wavelength: Spatial distribution of ammonia vapor

Icarus ◽  
2013 ◽  
Vol 226 (1) ◽  
pp. 641-654 ◽  
Author(s):  
A.L. Laraia ◽  
A.P. Ingersoll ◽  
M.A. Janssen ◽  
S. Gulkis ◽  
F. Oyafuso ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Thermal Emission ◽  
Ammonia Vapor

scholarly journals Ground-based remote sensing of thin clouds in the Arctic

2013 ◽  
Vol 6 (5) ◽  
pp. 1227-1243 ◽  
Author(s):  
T. J. Garrett ◽  
C. Zhao
Keyword(s):  
Water Vapour ◽  
Thermal Emission ◽  
Stratospheric Ozone ◽  
Microwave Radiometer ◽  
Single Layer ◽  
Primary Source ◽  
The Arctic ◽  
Liquid Water Path ◽  
Water Path ◽  
Microphysical Properties

Abstract. This paper describes a method for using interferometer measurements of downwelling thermal radiation to retrieve the properties of single-layer clouds. Cloud phase is determined from ratios of thermal emission in three "micro-windows" at 862.5 cm−1, 935.8 cm−1, and 988.4 cm−1 where absorption by water vapour is particularly small. Cloud microphysical and optical properties are retrieved from thermal emission in the first two of these micro-windows, constrained by the transmission through clouds of primarily stratospheric ozone emission at 1040 cm−1. Assuming a cloud does not approximate a blackbody, the estimated 95% confidence retrieval errors in effective radius re, visible optical depth τ, number concentration N, and water path WP are, respectively, 10%, 20%, 38% (55% for ice crystals), and 16%. Applied to data from the Atmospheric Radiation Measurement programme (ARM) North Slope of Alaska – Adjacent Arctic Ocean (NSA-AAO) site near Barrow, Alaska, retrievals show general agreement with both ground-based microwave radiometer measurements of liquid water path and a method that uses combined shortwave and microwave measurements to retrieve re, τ and N. Compared to other retrieval methods, advantages of this technique include its ability to characterise thin clouds year round, that water vapour is not a primary source of retrieval error, and that the retrievals of microphysical properties are only weakly sensitive to retrieved cloud phase. The primary limitation is the inapplicability to thicker clouds that radiate as blackbodies and that it relies on a fairly comprehensive suite of ground based measurements.

scholarly journals Whitecap and Wind Stress Observations by Microwave Radiometers: Global Coverage and Extreme Conditions

2019 ◽  
Vol 49 (9) ◽  
pp. 2291-2307 ◽  
Author(s):  
Paul A. Hwang ◽  
Nicolas Reul ◽  
Thomas Meissner ◽  
Simon H. Yueh
Keyword(s):  
Surface Wave ◽  
Wind Speed ◽  
Wind Stress ◽  
Thermal Emission ◽  
Microwave Radiometer ◽  
Wave Spectrum ◽  
Surface Wind ◽  
Unit Surface Area ◽  
Whitecap Coverage ◽  
Surface Wind Stress

AbstractWhitecaps manifest surface wave breaking that impacts many ocean processes, of which surface wind stress is the driving force. For close to a half century of quantitative whitecap reporting, only a small number of observations are obtained under conditions with wind speed exceeding 25 m s−1. Whitecap contribution is a critical component of ocean surface microwave thermal emission. In the forward solution of microwave thermal emission, the input forcing parameter is wind speed, which is used to generate the modeled surface wind stress, surface wave spectrum, and whitecap coverage necessary for the subsequent electromagnetic (EM) computation. In this respect, microwave radiometer data can be used to evaluate various formulations of the drag coefficient, whitecap coverage, and surface wave spectrum. In reverse, whitecap coverage and surface wind stress can be retrieved from microwave radiometer data by employing precalculated solutions of an analytical microwave thermal emission model that yields good agreement with field measurements. There are many published microwave radiometer datasets covering a wide range of frequency, incidence angle, and both vertical and horizontal polarizations, with maximum wind speed exceeding 90 m s−1. These datasets provide information of whitecap coverage and surface wind stress from global oceans and in extreme wind conditions. Breaking wave energy dissipation rate per unit surface area can be estimated also by making use of its linear relationship with whitecap coverage derived from earlier studies.

scholarly journals Studies of SNRS in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 313-313
Author(s):  
A. J. Turtle
Keyword(s):  
Spatial Distribution ◽  
Supernova Remnants ◽  
Thermal Emission ◽  
Magellanic Clouds ◽  
Diameter Distribution ◽  
Radio Luminosity ◽  
Radio Observations ◽  
X Ray

In the Magellanic Clouds about 60 confirmed supernova remnants (SNRs) or candidates are known. They have been detected by a combination of X-ray, optical and radio observations. Various statistical aspects of these SNRs will be considered including the implied supernova rate, the spatial distribution, the implications of the radio luminosity/diameter distribution for SNR evolution, and the relation to the extended non-thermal emission.

scholarly journals Analysis of Lightning and Precipitation Activities in Three Severe Convective Events Based on Doppler Radar and Microwave Radiometer over the Central China Region

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 298 ◽  
Author(s):  
Jing Sun ◽  
Jian Chai ◽  
Liang Leng ◽  
Guirong Xu
Keyword(s):  
Spatial Distribution ◽  
Doppler Radar ◽  
Microwave Radiometer ◽  
Convective Available Potential Energy ◽  
Inverse Correlation ◽  
Central China ◽  
Peak Time ◽  
Sudden Increase ◽  
Cloud Environment ◽  
Temporal And Spatial Distribution

Hubei Province Region (HPR), located in Central China, is a concentrated area of severe convective weather. Three severe convective processes occurred in HPR were selected, namely 14–15 May 2015 (Case 1), 6–7 July 2013 (Case 2), and 11–12 September 2014 (Case 3). In order to investigate the differences between the three cases, the temporal and spatial distribution characteristics of cloud–ground lightning (CG) flashes and precipitation, the distribution of radar parameters, and the evolution of cloud environment characteristics (including water vapor (VD), liquid water content (LWC), relative humidity (RH), and temperature) were compared and analyzed by using the data of lightning locator, S-band Doppler radar, ground-based microwave radiometer (MWR), and automatic weather stations (AWS) in this study. The results showed that 80% of the CG flashes had an inverse correlation with the spatial distribution of heavy rainfall, 28.6% of positive CG (+CG) flashes occurred at the center of precipitation (>30 mm), and the percentage was higher than that of negative CG (−CG) flashes (13%). Moreover, the quantity of thunderstorm cells in Case 1 was more than other cases, the peak time of +CG flashes was prior to that of total CG flashes in Case 2 and Case 3, and the time of +CG flashes’ peak in Case 2 was prior to that of precipitation at about 2 h. Based on the analysis of the cloud environment, there are three main reasons for the differences of CG flashes and precipitation. Firstly, the structure of the LWC vertical profile and the height of the LWC peak are different, and high LWC makes it difficult for the collision of ice particles to generate electricity. Secondly, the differences between convective available potential energy (CAPE), precipitation, and CG flashes is caused by the sudden increase of VD from 1.5 km to 3 km, and thirdly, the production of CG flashes is very sensitive to RH at the surface layer and the total CG flashes increase as the RH increasing.

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