Toward Understanding Direct Absorption and Grain Size Feedbacks by Dust Radiative Forcing in Snow With Coupled Snow Physical and Radiative Transfer Modeling

2019 ◽  
Vol 55 (8) ◽  
pp. 7362-7378 ◽  
Author(s):  
S. McKenzie Skiles ◽  
Thomas H. Painter
Keyword(s):  
Grain Size ◽  
Radiative Transfer ◽  
Radiative Forcing ◽  
Direct Absorption ◽  
Radiative Transfer Modeling

scholarly journals Seasonal and elevational variations of black carbon and dust in snow and ice in the Solu-Khumbu, Nepal and estimated radiative forcings

2014 ◽  
Vol 14 (15) ◽  
pp. 8089-8103 ◽  
Author(s):  
S. Kaspari ◽  
T. H. Painter ◽  
M. Gysel ◽  
S. M. Skiles ◽  
M. Schwikowski
Keyword(s):  
Water Resources ◽  
Radiative Transfer ◽  
Radiative Forcing ◽  
The Other ◽  
Radiative Forcings ◽  
Ice Melt ◽  
Radiative Transfer Modeling ◽  
The Himalaya ◽  
Snow And Ice Melt ◽  
Snow And Ice

Abstract. Black carbon (BC) and dust deposited on snow and glacier surfaces can reduce the surface albedo, accelerate snow and ice melt, and trigger albedo feedback. Assessing BC and dust concentrations in snow and ice in the Himalaya is of interest because this region borders large BC and dust sources, and seasonal snow and glacier ice in this region are an important source of water resources. Snow and ice samples were collected from crevasse profiles and snow pits at elevations between 5400 and 6400 m a.s.l. from Mera glacier located in the Solu-Khumbu region of Nepal during spring and fall 2009, providing the first observational data of BC concentrations in snow and ice from the southern slope of the Himalaya. The samples were measured for Fe concentrations (used as a dust proxy) via ICP-MS, total impurity content gravimetrically, and BC concentrations using a Single Particle Soot Photometer (SP2). Measured BC concentrations underestimate actual BC concentrations due to changes to the sample during storage and loss of BC particles in the ultrasonic nebulizer; thus, we correct for the underestimated BC mass. BC and Fe concentrations are substantially higher at elevations < 6000 m due to post-depositional processes including melt and sublimation and greater loading in the lower troposphere. Because the largest areal extent of snow and ice resides at elevations < 6000 m, the higher BC and dust concentrations at these elevations can reduce the snow and glacier albedo over large areas, accelerating melt, affecting glacier mass balance and water resources, and contributing to a positive climate forcing. Radiative transfer modeling constrained by measurements at 5400 m at Mera La indicates that BC concentrations in the winter–spring snow/ice horizons are sufficient to reduce albedo by 6–10% relative to clean snow, corresponding to localized instantaneous radiative forcings of 75–120 W m−2. The other bulk impurity concentrations, when treated separately as dust, reduce albedo by 40–42% relative to clean snow and give localized instantaneous radiative forcings of 488 to 525 W m−2. Adding the BC absorption to the other impurities results in additional radiative forcings of 3 W m−2. The BC and Fe concentrations were used to further examine relative absorption of BC and dust. When dust concentrations are high, dust dominates absorption, snow albedo reduction, and radiative forcing, and the impact of BC may be negligible, confirming the radiative transfer modeling. When impurity concentrations are low, the absorption by BC and dust may be comparable; however, due to the low impurity concentrations, albedo reductions are small. While these results suggest that the snow albedo and radiative forcing effect of dust is considerably greater than BC, there are several sources of uncertainty. Further observational studies are needed to address the contribution of BC, dust, and colored organics to albedo reductions and snow and ice melt, and to characterize the time variation of radiative forcing.

scholarly journals Microwave temperature and pressure measurements with the Odin satellite: I. Observational method

2002 ◽  
Vol 80 (4) ◽  
pp. 443-454 ◽  
Author(s):  
J R Pardo ◽  
M Ridal ◽  
D Murtagh ◽  
J Cernicharo
Keyword(s):  
Radiative Transfer ◽  
Outer Space ◽  
Atmospheric Temperature ◽  
Upper Atmosphere ◽  
Operational Mode ◽  
Altitude Range ◽  
Molecular Lines ◽  
Temperature And Pressure ◽  
Radiative Transfer Modeling ◽  
Temperature Vertical Profile

The Odin satellite is equipped with millimetre and sub-millimetre receivers for observations of several molecular lines in the middle and upper atmosphere of our planet (~25–100 km, the particular altitude range depending on the species) for studies in dynamics, chemistry, and energy transfer in these regions. The same receivers are also used to observe molecules in outer space, this being the astrophysical share of the project. Among the atmospheric lines that can be observed, we find two corresponding to molecular oxygen (118.75 GHz and 487.25 GHz). These lines can be used for retrievals of the atmospheric temperature vertical profile. In this paper, we describe the radiative-transfer modeling for O2 in the middle and upper atmosphere that we will use as a basis for the retrieval algorithms. Two different observation modes have been planned for Odin, the three-channel operational mode and a high-resolution mode. The first one will determine the temperature and pressure on an operational basis using the oxygen line at 118.75 GHz, while the latter can be used for measurements of both O2 lines, during a small fraction of the total available time for aeronomy, aimed at checking the particular details of the radiative transfer near O2 lines at very high altitudes (>70 km). The Odin temperature measurements are expected to cover the altitude range ~30–90 km. PACS Nos.: 07.57Mj, 94.10Dy, 95.75Rs

Retrieval of Cloud Optical Depth: Synergies between Whole Sky Imagers and Radiative Transfer Modeling.

2021 ◽  
Author(s):  
Caterina Peris-Ferrús ◽  
José Luís Gómez-Amo ◽  
Francesco Scarlatti ◽  
Roberto Román ◽  
Claudia Emde ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Optical Depth ◽  
Cloud Optical Depth ◽  
Radiative Transfer Modeling

scholarly journals High-resolution near-infrared speckle interferometry and radiative transfer modeling of the OH/IR star OH 104.9+2.4

2004 ◽  
Vol 424 (1) ◽  
pp. 165-177 ◽  
Author(s):  
D. Riechers ◽  
Y. Balega ◽  
T. Driebe ◽  
K.-H. Hofmann ◽  
A. B. Men'shchikov ◽  
...  
Keyword(s):  
High Resolution ◽  
Radiative Transfer ◽  
Near Infrared ◽  
Speckle Interferometry ◽  
Radiative Transfer Modeling
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