2002 ARCSS All-Hands Workshop

Radiation in the Arctic

Roger Colony¹, Alexander P. Makshtas^2
1International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Dr. P.O.Box 757335, Fairbanks, AK, 99775-7335, USA, Phone (907)474-5115, Fax (907)474-2643, rcolony@iarc.uaf.edu
²International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Dr. P.O.Box 757335, Fairbanks, AK, 99775-7335, USA, Phone (907)474-2678, Fax (907) 474-2643, makshtas@iarc.uaf.edu

The main parameters, affecting the characteristics of the radiation regime of the underlying surface are cloudiness, surface albedo, and transparency of atmosphere. The variations of transparency of different temporal scale are determined by the variations of total atmospheric water content and aerosol. The maximal changes of albedo in the Arctic relates with formation or melting of snow cover. The cloudiness determines the incoming short- and long-wave radiation near the surface. The variety of clouds forms; its water content, phase state, and spatial structure cause the obvious restrictions in the modeling of incoming radiation in cloudy condition. The tremendous numbers of data about polar atmosphere, including cloudiness and radiation, were collected during the field phase of SHEBA. But for climate investigations these data have the limited value due to temporal and, possibly, spatial variability of above mentioned characteristics of atmosphere.

It time the large number of radiation measurements and cloudiness observations (4-8 times per day) had been collected on coastal and island polar stations beginning 1930s and drifting stations "North Pole" from 1950–1991. The monthly mean values of radiation characteristics were published by Marshunova and Mishin (1994) and in the Arctic Meteorology and Climate Atlas (CD, 2000). These data were used for analysis the relation of monthly mean values of radiation parameters with monthly mean cloudiness, as well for investigations its interannual variability (e.g. Makshtas et al, 1999,). Evidently, the monthly mean data have the restricted value for development the adequate optical, radiation, cloudiness and atmospheric boundary layer models as well as for adequate climate estimations of radiation and turbulent heat fluxes due to averaging. The analysis of simultaneous non-averaging radiation, meteorological, radio sounding and snow data are needed. The other problem related with climate investigations is the comparison of data obtained with different instruments under the same weather conditions.

Our proposal is to create the new comprehensive data set on CD, combined the improved data of meteorological and snow measurements on the drifting stations, previously published on CD in 1994, the improved data set of "North Pole" stations radiosounding data (first version had been published by Kahl et al in 1993), the new data set of all available radiation measurements executed on drifting stations together with supplemented observations of cloudiness, and estimations of main parameters of energy exchange between atmosphere and sea ice in the Arctic Basin. Later, we think it would be very useful to create the similar data set for coastal and island polar stations.

In support to this proposal IARC execute now three funded by IARC-Frontier and NSF projects: "Intercalibration of the Russian and US sensors used for radiation measurements in the Polar Regions" (under logistical support of ARM), "The investigation of long-term variability of the free atmosphere in the Arctic", and " Based on the new archive of radio sounding data to develop and to validate atmospheric boundary layer parameterization". Additionally together with AARI we made preliminary research of possibility to use Sechi disk historical data for investigations of radiation regime of the Arctic shelf seas.

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