A compilation of the spectral absorption coefficient ice Ih is presented for temperatures near melting point, superseding Warren (1984). Significant changes are made to nearly all regions. The blue and near‐ultraviolet much weaker than prior estimates, which were already very small. near‐infrared differs by as a factor 2 from at some wavelengths. midinfrared rather uncertain in weakly absorbing regions 9 20 μ m. New far‐infrared measurements low extrapolated higher temperatures, shifts peak...

Abstract. Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts light-absorbing impurities in snow can dominate the absorption solar these reducing albedo relative to that pure snow, contributing surface energy budget leading earlier snowmelt. In this study Arctic surveyed for its content impurities, expanding updating 1983–1984 survey Clarke Noone. Samples were collected Alaska, Canada, Greenland, Svalbard, Norway, Russia, Ocean...

Light‐absorbing impurities in snow reduce albedo, producing a positive radiative forcing, warming the surface air and snowpack, accelerating melt. As melts, black carbon (BC) other insoluble light‐absorbing particulate (ILAP) are retained at because their scavenging efficiency with meltwater is <100%, so concentrations of ILAP increase melt, further reducing albedo. The magnitude this feedback depends on BC meltwater. We present results from field measurements vertical distribution near...

The angular pattern of sunlight reflected by snow is altered surface roughness, which in the interior Antarctica usually form meter‐scale longitudinal erosional features (sastrugi), whose axes align with direction strong winds. bidirectional reflectance distribution function (BRDF) changes over course a day as solar azimuth relative to sastrugi axis. normalized BRDF, or “anisotropic factor” R , was measured at South Pole Station from 22‐m tower 600, 660, and 900 nm wavelengths. similar three...

Abstract In three ship-based field experiments, spectral albedos were measured at ultraviolet, visible, and near-infrared wavelengths for open water, grease ice, nilas, young “grey” grey-white first-year both with without snow cover. From the measurements, broadband are computed clear cloudy sky, total solar spectrum as well visible bands used in climate models, Advanced Very High Resolution Radiometer (AVHRR) channels. The all-wave vary from 0.07 water to 0.87 thick snow-covered ice under...

Characteristics of springtime sea ice off East Antarctica were investigated during a cruise the Australian National Antarctic Research Expedition in October through December 1988. The fractional coverage ocean surface, thickness, and snow cover thickness for each several types estimated hourly region near ship. These observations carried out continuously 4 weeks ship was ice. Thin young prevalent throughout region, show systematic increase total area‐weighted pack (including open water area)...

Snow is a scattering-dominated medium whose scattering independent of wavelength at 350-600 nm. The attenuation solar radiation in snow can be used to infer the spectral absorption coefficient pure ice, by reference known value 600 method applied clean Antarctic snow; minimum 390 nm, and inferred lower than even lowest values Muon Neutrino Detector Array (AMANDA) experiment on glacier ice: length least 700 m, comparison with 240 m for AMANDA 10 from laboratory measurements.

Abstract Data from radiosondes, towers, and a thermistor string are used to characterize the temperature inversion at two stations: Amundsen-Scott Station South Pole, somewhat higher colder Dome C lower latitude. Ten years of data 22-m tower Pole analyzed. The include 2- temperatures for entire period 13-m last 2 yr. Statistics individual differences among three levels presented summer (December January) winter (April–September). relationships strength in lowest 22 m with wind speed downward...

Abstract Observations of temperature maxima at about 10 cm depth in cold Antarctic snow during summer have previously been explained by proposing that solar heating is distributed with whereas thermal infrared cooling localized the surface (the “solid-state greenhouse”). An increase from to (ΔΤ ≈ 4 K) found Rusin (1961) on Plateau was successfully reproduced Schlatter (1972) a combined radiative-transfer and heat-transfer model. However, when we improve model’s spectral resolution, solving...

Abstract Ice types, albedos and impurity content are characterized for the ablation zone of Greenland ice sheet in Kronprinz Christians Land (80° N, 24° W). Along this margin width is only about 8 km. The emergence melting old creates a surface layer dust that was originally deposited with snowfall high on sheet. This debris cover augmented by locally derived wind-blown sediment. Subsequently, particles often aggregate together to form centimetre-scale clumps melt into ice, creating...

The bidirectional reflectance distribution function (BRDF) of snow was measured from a 32‐m tower at Dome C, latitude 75°S on the East Antarctic Plateau. These measurements were made 96 solar zenith angles between 51° and 87° cover wavelengths 350–2400 nm, with 3‐ to 30‐nm resolution, over full range viewing geometry. BRDF 900 nm had previously been South Pole; C measurement that wavelength is similar. At both locations natural roughness surface causes anisotropy be less than flat snow....

Abstract The reduction of snow spectral albedo by black carbon (BC) and mineral dust, both alone in combination, is computed using radiative transfer modeling. Broadband shown for mass fractions covering the full range from pure to BC grain radii 5 µm 2500 µm, cover possible sizes on planetary surfaces. Parameterizations are developed opaque homogeneous snowpacks three broad bands used general circulation models several narrower bands. They functions radius fraction and/or dust valid up...

On the tropical oceans of a neo‐Proterozoic Snowball Earth, snow‐free ice would have existed in regions net sublimation. Photosynthesis could continued beneath this bare if it was sufficiently thin and clear. The steady state thickness is determined by necessity to balance upward conduction heat with three subsurface heating rates: flux from ocean base, latent freezing solar energy absorbed within ice. A preliminary study, using broadband model for radiation assuming large rate, had...

[1] Radiative transfer modeling of the reduction snow albedo by black carbon (BC) requires experimental verification. In natural is at most a few percent, and even with accurate measurements, attribution ambiguous because depends on other variables. this experiment, artificial snowpacks are made freezing water droplets produced snowmaking machine in an open field, using without added soot, amounts about 100 times background soot levels, so as to obtain large signal albedo. The optically...

Abstract. Atmospheric aqueous chemistry can have profound effects on our environment. The importance of within the atmospheric phase started gaining widespread attention in 1970s as there was growing concern over negative impacts ecosystem health from acid deposition. Research at mountaintop observatories including Whiteface Mountain (WFM) showed that gas sulfur dioxide emissions react cloud droplets to form sulfuric acid, which also impacted air quality by increasing aerosol mass loadings....

Spectral albedo was measured along a 6 km transect near the Allan Hills in East Antarctica. The traversed sequence from new snow through old snow, firn, and white ice, to blue showing systematic progression of decreasing at all wavelengths, as well specific surface area (SSA) increasing density. Broadband albedos under clear‐sky range 0.80 for 0.57 0.87 0.65 cloud. Both air bubbles cracks scatter sunlight; their contributions SSA were determined by microcomputed tomography on core samples...

Abstract. The spring 2008 Arctic Research of the Composition Troposphere from Aircraft and Satellites (ARCTAS) experiment was one major intensive field campaigns International Polar Year aimed at detailed characterization atmospheric physical chemical processes in region. A part this campaign a unique snow bidirectional reflectance on NASA P-3B aircraft conducted 7 15 April by Cloud Absorption Radiometer (CAR) jointly with airborne Ames Airborne Tracking Sunphotometer (AATS) ground-based...

Abstract Observations of temperature maxima at about 10 cm depth in cold Antarctic snow during summer have previously been explained by proposing that solar heating is distributed with whereas thermal infrared cooling localized the surface (the “solid-state greenhouse”). An increase from to (ΔΤ ≈ 4 K) found Rusin (1961) on Plateau was successfully reproduced Schlatter (1972) a combined radiative-transfer and heat-transfer model. However, when we improve model’s spectral resolution, solving...

When NaCl precipitates out of a saturated solution, it forms anhydrous crystals halite at temperatures above +0.11°C, but below this threshold instead as the dihydrate “hydrohalite,” · 2H 2 O. sea ice is cooled, hydrohalite begins to precipitate within brine inclusions about −23°C. In work, are examined in laboratory experiments: their formation, shape, and response warming desiccation. Sublimation surface low temperature leaves lag deposit hydrohalite, which has character fine powder. The...

Long-term records of condensed-phase chemical data are presented from the Adirondack Mountain region northern New York, USA. These particularly valuable due to combinations aerosol, cloud, and precipitation measurements. Objectives research this overview paper include evaluation emission reductions regulated air pollutants observed effects on measured deposition, as well implications changing pollutant concentration levels human health climate. Summer season cloud chemistry year-round wet...

Whiteface Mountain, with an elevation of 1483 m above sea level, is a relatively low mountain by global standards. At the same time, summit some 90 tree line and it fifth highest peak in Adirondack Mountain Range New York State. set apart from other High Peaks, providing ideal location for many types atmospheric measurements. The geographical northeastern U.S., lone massif character mountain, fact that very often enveloped cloud has made observatory attractive place scientific research. A...

Organic compounds are vital to atmospheric chemistry, with clouds playing a key role in their formation and transformation. Di-carboxylic organic anions, such as oxalate, act tracers for aqueous-phase chemical processes. This study presents summer measurements of three acids (formic, acetic, oxalic), inorganic cations cloud water, aerosol, droplet residual samples obtained 2018-2024 from the summit Whiteface Mountain (WFM), forested site Adirondack Mountains northern New York State....

Abstract To study near-surface heat flow on the Antarctíc ice sheet, snow temperatures were measured at South Pole Station to a depth of 3 m 15 min intervals during most 1992. Solar heating and water-vapor transport negligible 6 month Winter, as was inter-grain net thermal radiation, leaving conduction dominant heat-transport mechanism. The rate temperature change over smaller than that surface, by one order magnitude 20 cm two orders 1 depth. A finite-difference model, with only...

A multilevel spectral radiative transfer model is used to develop simple but accurate parameterizations for cloud transmittance as a function of optical depth, solar zenith angle, and surface albedo, use over snow, ice, water surfaces. The same functional form broadband transmittances, with different coefficients each interval. When the parameterization applied measurements "raw" (the ratio downward irradiance under measured clear sky at angle), an "effective" depth τ inferred field, which...