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Liu, J, Dedrick J, Russell LM, Senum GI, Uin J, Kuang CG, Springston SR, Leaitch WR, Aiken AC, Lubin D.  2018.  High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE. Atmospheric Chemistry and Physics. 18:8571-8587.   10.5194/acp-18-8571-2018   AbstractWebsite

Observations of the organic components of the natural aerosol are scarce in Antarctica, which limits our understanding of natural aerosols and their connection to seasonal and spatial patterns of cloud albedo in the region. From November 2015 to December 2016, the ARM West Antarctic Radiation Experiment (AWARE) measured submicron aerosol properties near McMurdo Station at the southern tip of Ross Island. Submicron organic mass (OM), particle number, and cloud condensation nuclei concentrations were higher in summer than other seasons. The measurements included a range of compositions and concentrations that likely reflected both local anthropogenic emissions and natural background sources. We isolated the natural organic components by separating a natural factor and a local combustion factor. The natural OM was 150 times higher in summer than in winter. The local anthropogenic emissions were not hygroscopic and had little contribution to the CCN concentrations. Natural sources that included marine sea spray and seabird emissions contributed 56 % OM in summer but only 3 % in winter. The natural OM had high hydroxyl group fraction (55 %), 6 % alkane, and 6 % amine group mass, consistent with marine organic composition. In addition, the Fourier transform infrared (FTIR) spectra showed the natural sources of organic aerosol were characterized by amide group absorption, which may be from seabird populations. Carboxylic acid group contributions were high in summer and associated with natural sources, likely forming by secondary reactions.

Lomax, AS, Lubin D, Whritner RH.  1995.  The Potential for Interpreting Total and Multiyear Ice Concentrations in Ssm/I 85.5 Ghz Imagery. Remote Sensing of Environment. 54:13-26.   10.1016/0034-4257(95)00082-c   AbstractWebsite

The 85.5 GHz vertically and horizontally polarized channels of the Special Sensor Microwave Inagers (SSM/1) aboard the Defense Meteorological Satellite Program (DMSP) spacecraft offer the potential to map sea ice with a spatial resolution of 12.5 km, a factor of two improvement over the popular National Aeronautics and Space Administration (NASA) Team algorithm, but with the limitation of increased atmospheric influence on the sea ice signal. Application of an algorithm for estimating total ice concentration from 85.5 GHz data, which exploits the large polarization for open water versus the small polarization for most ice types, reveals agreement with the NASA Team algorithm typically within. a standard deviation of +/- 3% for nearly cloud-free winter conditions. The uncertainty increases to a standard deviation of +/- 6% for cloudy winter conditions. In winter, volume scattering from multiyear ice has a noticeable impact on the 85.5 GHz brightness temperatures. By employing a polarization corrected temperature variable previously defined to isolate precipitation in mid-latitude DMSP imagery, it is possible to exploit the large differences in 85.5 GHz emissivity between first year and multiyear ice to interpret an 85.5 GHz image in terms of both total ice and multiyear ice concentration. Preliminary results, for nearly cloud-free winter conditions, reveal agreement between these interpretations and the NASA Team algorithm to within a standard deviation of +/- 6%, with slightly better agreement at Low multiyear ice concentration.

Lubin, D, Chen JP, Pilewskie P, Ramanathan V, Valero FPJ.  1996.  Microphysical examination of excess cloud absorption in the tropical atmosphere. Journal of Geophysical Research-Atmospheres. 101:16961-16972.   10.1029/96jd01154   AbstractWebsite

To investigate the excess shortwave absorption by clouds, a numerical cloud generation model has been coupled to a plane-parallel discrete ordinates radiative transfer model. The former was used in a time-dependent fashion to generate a cumulonimbus turret and three types of cirrus anvil (precipitating, extended, detached) representing three stages of cloud evolution outward from the turret. The cloud particle size distributions, as a function of altitude, were used as input to the radiative transfer model using indices of refraction for pure water and pure ice and equivalent sphere Mie theory. The radiative transfer model was used to calculate the ratio of cloud forcing at the surface to cloud forcing at the top of the atmosphere, both for the broadband shortwave and as a function of wavelength. Recent empirical studies have placed this cloud forcing ratio at around 1.5, and our coupled model results approach this value for small solar zenith angles, when the cloud contains large (>100 mu m) ice particles that absorb significantly in the near infrared (primarily the 1.6-mu m window). However, the empirical studies are based on diurnal averages, and our plane-parallel radiative transfer model yields an area and diurnally averaged cloud forcing ratio of only 1.18 for a tropical cumulonimbus and cirrus anvil system, primarily because of the rapid decrease of the ratio with solar zenith angle. The ratio decreases because of the increase in albedo with solar zenith angle, which is a characteristic feature of plane-parallel clouds. Adding dust or aerosol to the cloud layers, to make them absorb at visible wavelengths, makes the instantaneous cloud forcing ratio larger for an overhead Sun but also makes the solar zenith angle dependence in the cloud forcing ratio more pronounced. These two effects cancel, eliminating interstitial aerosol as a possible explanation for the excess cloud absorption in plane-parallel radiative transfer modeling. The strong dependence of the surface/top of the atmosphere cloud forcing ratio on solar zenith angle may be a fundamental defect with the plane-parallel approach to solar radiative transfer in a cloudy atmosphere.

Lubin, D, Chen B, Bromwich DH, Somerville RCJ, Lee WH, Hines KM.  1998.  The impact of Antarctic cloud radiative properties on a GCM climate simulation. Journal of Climate. 11:447-462.   10.1175/1520-0442(1998)011<0447:tioacr>2.0.co;2   AbstractWebsite

A sensitivity study to evaluate the impact upon regional and hemispheric climate caused by changing the optical properties of clouds over the Antarctic continent is conducted with the NCAR Community Model version 2 (CCM2). Sensitivity runs are performed in which radiation interacts with ice clouds with particle sizes of 10 and 40 mu m rather than with the standard 10-mu m water clouds. The experiments are carried out for perpetual January conditions with the diurnal cycle considered. The effects of these cloud changes on the Antarctic radiation budget are examined by considering cloud forcing at the top of the atmosphere and net radiation at the surface. Changes of the cloud radiative properties to those of 10-mu m ice clouds over Antarctica have significant Impacts on regional climate: temperature increases throughout the Antarctic troposphere by 1 degrees-2 degrees C and total cloud fraction over Antarctica is smaller than that of the control at low levels but is larger than that of the control in the mid- to upper troposphere. As a result of Antarctic warming and changes in the north-south temperature gradient, the drainage flows at the surface as well as the meridional mass circulation are weakened. Similarly, the circumpolar trough weakens significantly by 4-8 hPa and moves northward by about 4 degrees-5 degrees latitude. This regional mass field adjustment halves the strength of the simulated surface westerly winds. As a result of indirect thermodynamic and dynamic effects, significant changes are observed in the zonal mean circulation and eddies in the middle latitudes. In fact, the simulated impacts of the Antarctic cloud radiative alteration are not confined to the Southern Hemisphere. The meridional mean mass flux, zonal wind, and latent heat release exhibit statistically significant changes in the Tropics and even extratropics of the Northern Hemisphere. The simulation with radiative properties of 40-mu m ice clouds produces colder surface temperatures over Antarctica by up to 3 degrees C compared to the control. Otherwise, the results of the 40-mu m ice cloud simulation are similar to those of the 10-mu m ice cloud simulation.

Lubin, D, Frederick JE.  1991.  The Ultraviolet-Radiation Environment of the Antarctic Peninsula - the Roles of Ozone and Cloud Cover. Journal of Applied Meteorology. 30:478-493.   10.1175/1520-0450(1991)030<0478:tureot>2.0.co;2   AbstractWebsite

The National Science Foundation scanning spectroradiometer at Palmer Station, Antarctica (64-degrees-46'S, 64-degrees-04'W) provides hourly ground-based measurements of solar ultraviolet (UV) irradiance at the earth's surface. These measurements define the UV radiation environment of the region and, in conjunction with a daily record of sky conditions and radiative transfer modeling, permit a quantitative understanding of the role of cloud cover in regulating UV radiation levels at the Antarctic surface, including the period of the springtime ozone depletion. The transmission properties of cloud types over the Antarctic Peninsula are quantified by taking the ratio of UV-A irradiances measured under them to UV-A irradiances calculated for clear skies and the same solar zenith angle, and the results are then generalized to the UV-B. Under the average overcast sky in the region, UV irradiance at all wavelengths is slightly greater than half of the value for clear skies. Under the thickest overcast layers, UV irradiance at all wavelengths is roughly 20% what it would be if the sky were clear. In a seasonally averaged sense cloudiness has no effect on the percentage enhancement in UV-B surface irradiance that results from the springtime ozone depletion. However, when considering time scales of hours to several days, an increase in cloud cover can be discussed in terms of its ability to attenuate the solar irradiance; in some cases giving a surface UV-B level comparable to that found under an unperturbed ozone column and clear skies. Depending on the amount of ozone depletion and the type of cloud cover, there will always be a wavelength below which surface radiation levels are excessive during spring.

Lubin, D, Holm-Hansen O.  1995.  Atmospheric ozone and the biological impact of solar ultraviolet radiation. Encyclopedia of environmental biology. Vol. 1, A-E. 1( Nierenberg WA, Ed.).:147-168.: Academic Press Abstract
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Lubin, D.  1994.  The Role of the Tropical Super Greenhouse-Effect in Heating the Ocean Surface. Science. 265:224-227.   10.1126/science.265.5169.224   AbstractWebsite

Measurements made by a Fourier transform infrared (FTIR) spectroradiometer operating in the middle infrared (5 to 20 micrometers, with a spectral resolution of one inverse centimeter) imply that there is an anomalously large greenhouse effect over equatorial oceans that is caused by water vapor. As sea-surface temperature increased from 297 to 303 degrees kelvin, the net infrared cooling at the surface decreased by 30 to 50 watts per square meter. Thus, according to the FTIR data, the super greenhouse effect that had been inferred from satellite measurements contributes directly to radiative heating of the sea surface. The data demonstrate that most of this heating occurs in the middle infrared by means of the continuum emission window of water vapor and that tropical deep convection contributes substantially to this super greenhouse effect.

Lubin, D, Simpson AS.  1997.  Measurement of surface radiation fluxes and cloud optical properties during the 1994 Arctic Ocean Section. Journal of Geophysical Research-Atmospheres. 102:4275-4286.   10.1029/96jd03215   AbstractWebsite

During a voyage to the north pole from Alaska by the icebreakers USCGC Polar Sea and Canadian CGC Louis S. St.-Laurent (the 1994 Arctic Ocean Section, July 24 to September 3) an atmospheric radiation and remote sensing experiment measured downwelling shortwave and longwave radiation reaching the sea ice surface. The experiment included a Fourier transform infrared (FTIR) spectroradiometer which measured zenith radiance at 1 cm(-1) resolution in the middle infrared wavelength range 5-20 mu m, an Eppley pyranometer measuring most of the downwelling shortwave flux (0.28-2.80 mu m), an Eppley pyranometer measuring the downwelling near-infrared flux (0.78-2.80 mu m), and an Eppley pyrgeometer measuring the downwelling longwave flux. In conjunction with a discrete-ordinates radiative transfer model, the FTIR emission spectra are used to estimate 8-12 mu m cloud emissivity and effective radius of the cloud droplet size distribution. The broadband shortwave flux measurements are used to estimate shortwave cloud scattering optical depth. Most of the FTIR emission spectra recorded under overcast skies are consistent with cloud effective radius in the range 10-12 mu m, but 27% of the spectra are more consistent with the range 4-6 mu m, suggesting an occasional continental aerosol influence to Arctic cloud microphysics. The average daily shortwave cloud-scattering optical depth ranged from 2 to 46, which is similar to a range inferred from radiometer data recorded at Barrow, Alaska, during the same season. The downwelling shortwave flux measurements and estimates of net surface flux are generally consistent with a four-decade Russian climatology but also suggest that the frequency of cloud cover sampled during the 1994 Arctic Ocean Section was somewhat larger than the climatological average. These radiation measurement data from the 1994 Arctic Ocean Section should be useful for examining the treatment of atmospheric radiation and surface energy input in Arctic climate model simulations.

Lubin, D, Vogelmann AM.  2007.  Expected magnitude of the aerosol shortwave indirect effect in springtime Arctic liquid water clouds. Geophysical Research Letters. 34   10.1029/2006gl028750   AbstractWebsite

Radiative transfer simulations are used to assess the expected magnitude of the diurnally-averaged shortwave aerosol first indirect effect in Arctic liquid water clouds, in the context of recently discovered longwave surface heating of order 3 to 8 W m(-2) by this same aerosol effect detected at the Barrow, Alaska, ARM Site. We find that during March and April, shortwave surface cooling by the first indirect effect is comparable in magnitude to the longwave surface heating. During May and June, the shortwave surface cooling exceeds the longwave heating. Due to multiple reflection of photons between the snow or sea ice surface and cloud base, the shortwave first indirect effect may be easier to detect in surface radiation measurements than from space.

Lubin, D, Holm-Hansen O, Helbling EW.  1993.  Ultraviolet radiation and its effects on organisms in aquatic environments. Environmental UV photobiology. ( Young AR, Ed.).:379-345., New York: Plenum Press Abstract
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Lubin, D.  1994.  Infrared Radiative Properties of the Maritime Antarctic Atmosphere. Journal of Climate. 7:121-140.   10.1175/1520-0442(1994)007<0121:irpotm>2.0.co;2   AbstractWebsite

The longwave radiation environment of the Antarctic Peninsula and Southern Ocean has been investigated using radiometric Fourier Transform Infrared (FTIR) measurements of atmospheric emission in conjunction with detailed radiative transfer theory. The California Space Institute FTIR Spectroradiometer was deployed at Palmer Station, Antarctica (64 degrees 46'S, 64 degrees 04'W), where it made zenith sky emission measurements several times daily between 25 August 1991 and 17 November 1991. Emission spectra covered the entire middle infrared (5-20 mu m) with one inverse centimeter spectral resolution. For FTIR data obtained under cloudy skies, a least-squares algorithm is used to match the emission spectra with discrete-ordinate radiative transfer calculations that are based on marine cloud microphysics. This algorithm provides a determination of cloud emissivity, and useful estimates of cloud optical depth and equivalent radius of the droplet size distribution. Temperatures in the lower troposphere between 259 K and 273 K diminish the radiative importance of water vapor and enhance the importance of clouds and CO2 relative to midlatitudes. Springtime variability in stratospheric temperature and ozone abundance has a small but noticeable impact of about 1.0 W m(-2) on surface longwave flux under clear skies. The mid-IR window emissivities of low stratiform clouds are most often between 0.90 and 0.98, with few as large as unity. Most low stratiform clouds appear to have moderate mid-IR optical depth (5-10), but relatively large equivalent radius (9-11 mu m). However, clouds with base height between 1 and 2 km have noticeably smaller emissivities and optical depths. The emissivity of maritime antarctic clouds is determined to be smaller for a given liquid water path than the parameterization used in the NCAR Community Climate Model (CCM1), and an appropriate mass absorption coefficient for antarctic clouds is 0.065 m(2) g(-1) for the mid-IR window.

Lubin, D, Tytler D, Kirkman D.  2012.  Frequency of Maunder minimum events in solar-type stars inferred from activity and metallicity observations.. The Astrophysical Journal Letters. (747 L32)   10.1088/2041-8205/747/2/L32  
Lubin, D, Mitchell BG, Frederick JE, Alberts AD, Booth CR, Lucas T, Neuschuler D.  1992.  A Contribution toward Understanding the Biospherical Significance of Antarctic Ozone Depletion. Journal of Geophysical Research-Atmospheres. 97:7817-7828.   10.1029/91JD01400   AbstractWebsite

Measurements of biologically active UV radiation made by the National Science Foundation (NSF) scanning spectroradiometer (UV-monitor) at Palmer Station. Antarctica, during the Austral springs of 1988, 1989, and 1990 are presented and compared. Column ozone abundance above Palmer Station is computed from these measurements using a multiple wavelength algorithm. Two contrasting action spectra (biological weighting functions) are used to estimate the biologically relevant (dose from the spectral measurements: a standard weighting function for damage to DNA, and a new action spectrum representing the potential for photosynthesis inhibition in Antarctic phytoplankton. The former weights only UV-B wavelengths (280-320 nm) and gives the most weight to wavelengths shorter than 300 nm, while the latter includes large contributions out to 355 nm. The latter is the result of recent Antarctic field work and is relevant in that phytoplankton constitute the base of the Antarctic food web. The modest ozone hole of 1988, in which the ozone abundance above Palmer Station never fell below 200 Dobson units (DU), brought about summerlike doses of DNA-effective UV radiation 2 months early, but UV doses which could inhibit photosynthesis in phytoplankton did not exceed a clear-sky "maximum normal" dose for that time of year. The severe ozone holes of 1989 and 1990, in which the ozone abundance regularly fell below 200 DU, brought about increases in UV surface irradiance weighted by either action spectrum. Ozone abundances and dose-weighted irradiances provided by the NSF UV-monitor are used to derive the radiation amplification factors (RAFs) for both DNA-effective irradiance and phytoplankton-effective irradiance. The RAF for DNA-effective irradiance is nonlinear in ozone abundance and is in excess of the popular "two for one" rule, while the RAF for phytoplankton-effective irradiance approximately follows a "one for one" rule.

Lubin, D, Li W, Dustan P, Mazel CH, Stamnes K.  2001.  Spectral signatures of coral reefs: Features from space. Remote Sensing of Environment. 75:127-137.   10.1016/s0034-4257(00)00161-9   AbstractWebsite

The special signatures of coral reefs and related scenes, as they would be measured above the Earth's atmosphere, are calculated using a coupled atmosphere-ocean discrete ordinates radiative transfer model. Actual measured reflectance spectra from field work are used as input data. Four coral species are considered, to survey the natural range of coral reflectance: Montastrea cavernosa, Acropora palmata, Dichocoenia stokesii, and Siderastrea siderea. Four noncoral objects associated with reefs are also considered: sand, coralline algae, green macroalgae, and algal turf. The reflectance spectra as would be measured at the top of the atmosphere are substantially different from the in situ spectra, due to differential attenuation by the water column and, most importantly, by atmospheric Rayleigh scattering. The result is that many of the spectral features that can be used to distinguish coral species from their surroundings or from one another, which have been used successfully with surface or aircraft data, would be obscured in spectral measurements from a spacecraft. However, above the atmosphere, the radiance contrasts between most coral species and most brighter noncoral objects remain noticeable for water column depths up to 20 m. Over many spectral intervals, the reflectance from dark coral under shallow water is smaller than that of deep water. The maximum top-of-atmosphere radiances, and maximum contrasts between scene types, occur between 400 nm and 600 nm. This study supports the conclusions of recent satellite reef mapping exercises, suggesting that coral reef identification should be feasible using satellite remote sensing, but that detailed reef mapping (e.g., species identification) may be more difficult. (C) Elsevier Science Inc., 2001.

Lubin, D, Vogelmann AM.  2010.  Observational quantification of a total aerosol indirect effect in the Arctic. Tellus Series B-Chemical and Physical Meteorology. 62:181-189.   10.1111/j.1600-0889.2010.00460.x   AbstractWebsite

We use 6 yr of multisensor radiometric data (1998-2003) from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program to provide an observational quantification of the short-wave aerosol first indirect effect in the Arctic. Combined with the previously determined long-wave indirect effect, the total (short-wave and long-wave) first indirect effect in the high Arctic is found to yield a transition from surface warming of +3 W m(-2) during March to a cooling of -11 W m(-2) during May, therefore altering the seasonal cycle of energy input to the Arctic Earth atmosphere system. These data also reveal evidence of a first indirect effect that affects optically thinner clouds during summer. which may represent an additional negative climate feedback that responds to a warming Arctic Ocean with retreating sea ice.

Lubin, D, Arrigo KR, van Dijken GL.  2004.  Increased exposure of Southern Ocean phytoplankton to ultraviolet radiation. Geophysical Research Letters. 31   10.1029/2004gl019633   AbstractWebsite

Satellite remote sensing of both surface solar ultraviolet radiation (UVR) and chlorophyll over two decades shows that biologically significant ultraviolet radiation increases began to occur over the Southern Ocean three years before the ozone "hole'' was discovered. Beginning in October 1983, the most frequent occurrences of enhanced UVR over phytoplankton-rich waters occurred in the Weddell Sea and Indian Ocean sectors of the Southern Ocean, impacting 60% of the surface biomass by the late 1990s. These results suggest two reasons why more serious impacts to the base of the marine food web may not have been detected by field experiments: ( 1) the onset of UVR increases several years before dedicated field work began may have impacted the most sensitive organisms long before such damage could be detected, and ( 2) most biological field work has so far not taken place in Antarctic waters most extensively subjected to enhanced UVR.

Lubin, D, Weber PG.  1995.  The Use of Cloud Reflectance Functions with Satellite Data for Surface Radiation Budget Estimation. Journal of Applied Meteorology. 34:1333-1347.   10.1175/1520-0450(1995)034<1333:tuocrf>2.0.co;2   AbstractWebsite

The bidirectional reflectance distribution function (BRDF) of an overcast atmosphere above an ocean surface has been calculated as a function of wavelength using a discrete-ordinates radiative transfer model. This plane-parallel BRDF appears qualitatively similar to the empirically derived angular dependence models from the Earth Radiation Budget Experiment. But when these two different BRDFs are used to estimate net shortwave flux at the ocean surface, discrepancies of 20-60 W m(-2) can occur between the respective net surface nux estimations. When using either BRDF with Advanced Very High Resolution Radiometer data for surface radiation budget estimation, this uncertainty can be minimized by restricting the satellite viewing( polar) angle to between 30 degrees and 50 degrees. Accurate measurements of the planetary BRDF would help resolve these differences.

Lubin, D, Vogelmann AM.  2006.  A climatologically significant aerosol longwave indirect effect in the Arctic. Nature. 439:453-456.   10.1038/nature04449   AbstractWebsite

The warming of Arctic climate and decreases in sea ice thickness and extent(1,2) observed over recent decades are believed to result from increased direct greenhouse gas forcing, changes in atmospheric dynamics having anthropogenic origin(3-5), and important positive reinforcements including ice - albedo and cloud - radiation feedbacks(6). The importance of cloud - radiation interactions is being investigated through advanced instrumentation deployed in the high Arctic since 1997 (refs 7, 8). These studies have established that clouds, via the dominance of longwave radiation, exert a net warming on the Arctic climate system throughout most of the year, except briefly during the summer(9). The Arctic region also experiences significant periodic influxes of anthropogenic aerosols, which originate from the industrial regions in lower latitudes(10). Here we use multisensor radiometric data(7,8) to show that enhanced aerosol concentrations alter the microphysical properties of Arctic clouds, in a process known as the 'first indirect' effect(11,12). Under frequently occurring cloud types we find that this leads to an increase of an average 3.4 watts per square metre in the surface longwave fluxes. This is comparable to a warming effect from established greenhouse gases and implies that the observed longwave enhancement is climatologically significant.

Lubin, D, Jensen EH.  1997.  Satellite mapping of solar ultraviolet radiation at the earth's surface. Solar ultraviolet radiation : modelling, measurements, and effects. ( Zerefos CS, Bais AF, Eds.)., Berlin; New York: Springer Abstract
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Lubin, D, Frederick JE, Booth CR, Lucas T, Neuschuler D.  1989.  Measurements of Enhanced Springtime Ultraviolet-Radiation at Palmer-Station, Antarctica. Geophysical Research Letters. 16:783-785.   10.1029/GL016i008p00783   AbstractWebsite

Measurements of ultraviolet solar spectra from Palmer Station, Antarctica have defined the surface radiation environment of the region during the Austral spring of 1988. At wavelengths where absorption by ozone is negligible, 335–345 nm, the noontime irradiances show the expected gradual increase from the first day of measurements, 19 September, through 21 December. Large variations related to cloudiness are imposed on this background. At wavelengths less than 310 nm the influence of the 1988 ozone “hole” is apparent. The noontime irradiance observed in the wavelength band 295–305 nm on 19 October, two months prior to summer solstice, exceeded any value measured through 21 December.

Lubin, D, Gautier C.  1992.  Fourier transform infrared spectroradiometer measurements of atmospheric longwave emission over Palmer Station, spring 1991. Antarctic Journal of the United States. 27:276. Abstract

Presents the results of Fourier Transform Infrared spectroradiometer measurements of atmospheric longwave emission from the zenith sky over Palmer Station in Antarctica. Overcast as the most common sky condition in the area; Definition of longwave cloud forcing at the earth's surface.

Lubin, D, Morrow E.  2001.  Ultraviolet radiation environment of Antarctica 1. Effect of sea ice on top-of-atmosphere albedo and on satellite retrievals. Journal of Geophysical Research-Atmospheres. 106:33453-33461.   10.1029/2001jd000687   AbstractWebsite

The backscattered ultraviolet radiance measured by the Total Ozone Mapping Spectrometer (TOMS) over the Southern Ocean is influenced by both cloud cover and sea ice concentration. In TOMS data alone, these influences cannot be separated. To assess the relative importance of cloud opacity and sea ice concentration, TOMS level 2 data are colocated with AVHRR and SSM/I data. AVHRR provides independent cloud identification at a spatial resolution sufficient to estimate cloud fraction within a TOMS level 2 footprint, while the SSM/I provides useful estimates of sea ice concentration over clear and cloudy scenes. The sea ice cover is shown to have a stronger influence than cloud cover on the backscattered ultraviolet radiance at the top of the atmosphere. Over overcast scenes the mean TOMS reflectivity increases from 45 to 84% as the underlying sea ice concentration increases from 0 to 1. Over scenes containing sea ice concentrations greater than 0.5, the increase in TOMS-measured radiance with increasing cloud amount (0-1) is generally less than 30% and is negligible over high sea ice concentrations. Over clear-sky scenes the characteristic UV-A albedos of the sea ice components of the scenes are retrieved from the TOMS data. These albedos range from 0.19 +/- 0.14 for sea ice concentration 0.1, increasing rapidly to 0.53 +/- 0.15 for sea ice concentration 0.3, and then approximately linearly to 0.80 +/- 0.11 for sea ice concentration 1.0. There is the potential to develop a climatology of surface ultraviolet and photosynthetically active radiation for southern high latitudes, which utilizes a combination of TOMS and SSM/I data. Such a climatology could cover the entire Southern Ocean throughout the duration of the modern springtime ozone depletion phenomenon. Analysis of uncertainties related to sea ice concentration retrieval from SSM/I, and related uncertainties in surface albedo identification and their influence on the estimated surface radiative flux, shows that such a climatology would have the most quantitative value for sea ice concentrations less than 0.5.

Lubin, D, Massom R.  2007.  Remote sensing of Earth's polar regions - Opportunities for computational science. Computing in Science & Engineering. 9:58-71.   10.1109/mcse.2007.16   AbstractWebsite

Polar remote sensing offers numerous opportunities for computer scientists, including spacecraft design and data processing, the development of algorithms for geophysical product retrieval, operational assistance for aircraft and ship navigation, and database management at national archives.

Lubin, D, Simpson AS.  1994.  The Longwave Emission Signature of Urban Pollution - Radiometric Ftir Measurement. Geophysical Research Letters. 21:37-40.   10.1029/93gl03374   AbstractWebsite

Air pollutants trapped beneath frequent temperature inversions in the Los Angeles basin bring about surface radiance enhancements of up to fifty percent in the middle-infrared window (8-12 microns). This constitutes an anthropogenic modification to the downwelling longwave flux which can be as large as 9 W/m2. A Fourier Transform Infrared (FTIR) spectroradiometer has been used to measure middle-infrared atmospheric emission spectra under Los Angeles smog, and these 1 cm-1 resolution spectra demonstrate that both anthropogenic aerosols and increased tropospheric ozone abundance contribute to enhancements in surface longwave radiation.