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Satheesh, SK, Lubin D.  2003.  Short wave versus long wave radiative forcing by Indian Ocean aerosols: Role of sea-surface winds. Geophysical Research Letters. 30   10.1029/2003gl017499   AbstractWebsite

[1] Recent observations over the Indian Ocean have demonstrated aerosol short wave absorption as high as 20 to 25 W m(-2). The aerosol net radiative forcing reduces substantially while considering the broad spectrum including the long wave region (due to large infrared forcing which is opposite in sign). At highwinds, presence of large amounts of sea-salt aerosols (absorbing in infrared) enhances the infrared forcing; hence reduces the net radiative forcing. In this paper, we examine the role of sea-surface winds (which enhance sea-salt aerosols) on long wave aerosol forcing. Even at moderate winds (6-10 m s(-1)), the short wave forcing reduces by similar to45% due to the dominance of sea-salt aerosols. At high winds (>10 m s(-1)), a major fraction of the long wave forcing is contributed by sea-salt (more than 70%). Our studies show that neglecting aerosol long wave radiative forcing can cause large errors in climate models.

Scott, RC, Nicolas JP, Bromwich DH, Norris JR, Lubin D.  2019.  Meteorological drivers and large-scale climate forcing of West Antarctic Surface Melt. Journal of Climate. 32:665-684.   10.1175/jcli-d-18-0233.1   AbstractWebsite

Understanding the drivers of surface melting in West Antarctica is crucial for understanding future ice loss and global sea level rise. This study identifies atmospheric drivers of surface melt on West Antarctic ice shelves and ice sheet margins and relationships with tropical Pacific and high-latitude climate forcing using multidecadal reanalysis and satellite datasets. Physical drivers of ice melt are diagnosed by comparing satellite-observed melt patterns to anomalies of reanalysis near-surface air temperature, winds, and satellite-derived cloud cover, radiative fluxes, and sea ice concentration based on an Antarctic summer synoptic climatology spanning 1979-2017. Summer warming in West Antarctica is favored by Amundsen Sea (AS) blocking activity and a negative phase of the southern annular mode (SAM), which both correlate with El Nino conditions in the tropical Pacific Ocean. Extensive melt events on the Ross-Amundsen sector of the West Antarctic Ice Sheet (WAIS) are linked to persistent, intense AS blocking anticyclones, which force intrusions of marine air over the ice sheet. Surface melting is primarily driven by enhanced downwelling longwave radiation from clouds and a warm, moist atmosphere and by turbulent mixing of sensible heat to the surface by fohn winds. Since the late 1990s, concurrent with ocean-driven WAIS mass loss, summer surface melt occurrence has increased from the Amundsen Sea Embayment to the eastern Ross Ice Shelf. We link this change to increasing anticyclonic advection of marine air into West Antarctica, amplified by increasing air-sea fluxes associated with declining sea ice concentration in the coastal Ross-Amundsen Seas.

Scott, RC, Lubin D.  2016.  Unique manifestations of mixed-phase cloud microphysics over Ross Island and the Ross Ice Shelf, Antarctica. Geophysical Research Letters. 43:2936-2945.   10.1002/2015gl067246   AbstractWebsite

Spaceborne radar and lidar observations from the CloudSat and CALIPSO satellites are used to compare seasonal variations in the microphysical and radiative properties of clouds over Ross Island, Antarctica, with two contrasting Arctic atmospheric observatories located in Barrow, Alaska, and Summit, Greenland. At Ross Island, downstream from recurrent intrusions of marine air over the West Antarctic Ice Sheet and eastern Ross Ice Shelf, clouds exhibit a tendency toward the greatest geometrical thickness and coldest temperatures in summer, the largest average ice water content, IWC, at low altitude during summer and autumn, the most abundant IWC at cold mixed-phase temperatures (-40 degrees C

Scott, RC, Lubin D, Vogelmann AM, Kato S.  2017.  West Antarctic Ice Sheet Cloud Cover and Surface Radiation Budget from NASA A-Train Satellites. Journal of Climate. 30:6151-6170.   10.1175/jcli-d-16-0644.1   AbstractWebsite

Clouds are an essential parameter of the surface energy budget influencing the West Antarctic Ice Sheet (WAIS) response to atmospheric warming and net contribution to global sea level rise. A 4-yr record of NASA A-Train cloud observations is combined with surface radiation measurements to quantify the WAIS radiation budget and constrain the three-dimensional occurrence frequency, thermodynamic phase partitioning, and surface radiative effect of clouds over West Antarctica (WA). The skill of satellite-modeled radiative fluxes is confirmed through evaluation against measurements at four Antarctic sites (WAIS Divide ice camp and Neumayer, Syowa, and Concordia stations). Owing to perennial high-albedo snow and ice cover, cloud infrared emission dominates over cloud solar reflection and absorption leading to a positive net all-wave cloud radiative effect (CRE) at the surface, with all monthly means and 99.15% of instantaneous CRE values exceeding zero. The annual-mean CRE at the WAIS surface is 34 W m−2, representing a significant cloud-induced warming of the ice sheet. Low-level liquid-containing clouds, including thin liquid water clouds implicated in radiative contributions to surface melting, are widespread and most frequent in WA during the austral summer. In summer, clouds warm the WAIS by 26 W m−2, on average, despite maximum offsetting shortwave CRE. Glaciated cloud systems are strongly linked to orographic forcing, with maximum incidence on the WAIS continuing downstream along the Transantarctic Mountains.

Smith, WL, Hansen C, Bucholtz A, Anderson BE, Beckley M, Corbett JG, Cullather RI, Hines KM, Hofton M, Kato S, Lubin D, Moore RH, Rosenhaimer MS, Redemann J, Schmidt S, Scott R, Song S, Barrick JD, Blair JB, Bromwich DH, Brooks C, Chen G, Cornejo H, Corr CA, Ham SH, Kittelman AS, Knappmiller S, LeBlanc S, Loeb NG, Miller C, Nguyen L, Palikonda R, Rabine D, Reid EA, Richter-Menge JA, Pilewswskie P, Shinozuka Y, Spangenberg D, Stackhouse P, Taylor P, Thornhill KL, Van Gilst D, Winstead E.  2017.  ARCTIC RADIATION-ICEBRIDGE SEA AND ICE EXPERIMENT The Arctic Radiant Energy System during the Critical Seasonal Ice Transition. Bulletin of the American Meteorological Society. 98:1399-1426.   10.1175/bams-d-14-00277.1   AbstractWebsite

Through ARISE, NASA acquired unique aircraft data on clouds, atmospheric radiation and sea ice properties during the critical period between the sea ice minimum in late summer and autumn and the commencement of refreezing.

Suzuki, N, Tytler D, Kirkman D, O'Meara JM, Lubin D.  2005.  Predicting QSO continua in the Ly alpha forest. Astrophysical Journal. 618:592-600.   10.1086/426062   AbstractWebsite

We present a method to make predictions with sets of correlated data values, in this case QSO flux spectra. We predict the continuum in the Lyalpha forest of a QSO, from 1020 to 1216 8, using the spectrum of that QSO from 1216 to 1600 Angstrom. We find correlations between the unabsorbed flux in these two wavelength regions in the Hubble Space Telescope (HST) spectra of 50 QSOs. We use principal component analysis to summarize the variety of these spectra, relate the weights of the principal components for 1020-1600 Angstrom to the weights for 1216-1600 Angstrom, and apply this relation to make predictions. We test the method on the HST spectra and find an average absolute flux error of 9%, with a range of 3%-30%, where individual predictions are systematically too low or too high. We mention several ways in which the predictions might be improved.