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    Weather balloon soundings have been collected since the mid-1990's from NOAA ships during TAO mooring cruises. Sets of soundings are available at 6 month intervals, with some substantial gaps, mostly along the 110 W and 95 W lines.

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    Changes are occurring in the Arctic which appear to have begun in the late 1960s and have accelerated in the 1990s. These include tropospheric temperature warming, reductions in sea ice extent, and increased variability in snow cover. In this paper, we will focus our study on the western Arctic and on the temperature changes during the last twenty years. The data sets for the study are NCEP/NCAR reanalysis and TOVS Path-P gridded data. In terms of the temperature decadal change, both TOVS and NCEP reanalysis show similar patterns, however the magnitude of the change differs. Both analyses show a strong warming during spring time in the lower troposphere with cooling in the stratosphere. In general the magnitude of warm anomalies decrease with height, and change sign above the 300 hpa level. It is clear that the 1990s on the whole were older aloft, and warmer near the surface, than previous decades. However, each individual year contributes differently to the composite. Our analysis focuses on the connection between the enhanced polar vortex associated with cold anomalies aloft and surface warming at lower levels, when the polar vortex breaks down. Data can obtained from the NCEP/NCAR Reanalysis Project at the NOAA-CIRES Climate Diagnostics Center. http://www.cdc.noaa.gov/cdc/reanalysis/

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    The lower troposphere of the western Arctic (eastern Siberia to western Canada) was relatively warm during spring in the 1990s. Based on the NCEP-NCAR reanalysis, supplemented by the Television Infrared Observation Satellite (TIROS) Operation Vertical Sounder (TOVS) Polar Pathfinder dataset, this warmth a result of a recent increase in the frequency of warm months, compared to the previous four decades. The primary difference between four notably warm springs in the 1990s and four cold springs in the 1980s was the sense of the horizontal advection term in a lower-tropospheric heat budget for northern Alaska/southern Beaufort Sea. While the horizontal advection of heat was highly episodic, it was related to changes in the mean circulation at low levels, in particular a shift from anomalous northeasterly flow in the 1980s to anomalous southwesterly flow in the 1990s during March and April. This change in the low-level winds in the western Arctic coincided with a systematic shift in the Arctic Oscillation (AO) near the end of the 1980s, and reflects the equivalent barotropic nature of the AO. The stratospheric temperature anomalies associated with the AO were greatest in March; the low-level wind anomalies brought about near-surface temperature anomalies in northern Alaska that peaked in April. In addition to substantial decadal differences, there was considerable month-to-month and year-to-year variability within the last two decades. Data can obtained from the NCEP/NCAR Reanalysis Project at the NOAA-CIRES Climate Diagnostics Center. [ Reference: Overland, J.E., M.Wang, and N.A. Bond: J. Clim., 15(13), 1702-1716 (2002) ]

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    Measurements taken during the Storm Transfer and Response Experiment (STREX) are used to analyze boundary layer structures and processes in North Pacific storms. Heat and moisture transfers at the surface and through the top of the boundary layer are evaluated for three cases with warm, southerly flow ahead of cold fronts and two cases of cooler, westerly and northern flow behind fronts. The prefrontal boundary layers are nearly neutrally stratified and surface heat and moisture fluxes are small. Surface fluxes tend to be downward just ahead of the fronts and are of greater magnitude during stronger storms. Entrainment fluxes at the top of the prefrontal boundary layers are generally larger than surface fluxes and are the dominant sources of heating for the boundary layers. Entrainment rates determined from budgets compare well with laboratory studies of shear-driven entrainment. In the postfrontal cases, surface heat and moisture fluxes are the dominant sources of total heating within the boundary layers. Entrainment velocities are larger in postfrontal than prefrontal regions, but entrainment has only a small and positive net effect on the total heat content. In postfrontal transition layers the Richardson numbers are large, and entrainment is forced by turbulence generated by buoyancy in the surface layers and radiative and evaporative cooling from the tops of stratocumulus clouds. Cumulus-scale penetrative convection represents the major sink of boundary layer moisture for one case with a long atmospheric fetch over the ocean.

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    This study describes the structure of an oceanic cold front from research aircraft observations taken during the OCEAN STORMS field experiment. Synoptic and mesoscale analyses compare the structure of an upper-level jet-front system observed slightly downstream from the wind speed maximum (exit region) to its structure in the upstream entrance region. Stratospheric potential vorticity and ozone were found within the frontal zone down to ~800 mb. Microscale analyses of the front near the sea surface were carried out for a portion of the front having the signature of a "rope" cloud (shallow cumulus line) in satellite imagery. A narrow (<1 km) zone of upward motion (~4 ms) and of horizontal shear (~10 s) characterized the front near the surface. Significant alongfront variability was found, including lateral displacements in the frontal zone where there were weaker updrafts; similar structures have been previously observed along precipitating fronts using Doppler radar. Pressure perturbations measured directly by the aircraft resemble pressure perturbations for a deeper, precipitating front that were derived indirectly from Doppler radar data. Results show that the frontal zone was well defined through the depth of the troposphere, tapering from a width of ~100 km in the upper troposphere to ~1 km at the surface. The collapse of the front to such a narrow scale within the boundary layer occurred in the absence of precipitation, and obviously, in the absence of topographical influences.

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    Daily or twice daily gridded atmospheric data (~ 380 km grid spacing at 60 N) for the period 1946 - 1994. Fields available include sea-level pressure (SLP) and 500 mb height from 1946 through 1961 and additional operationally-analyzed atmospheric fields from 1962 through 1994.

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    This data set contains total column aerosol optical thickness retrievals calculated from channel 2 albedo observations (using the SST cloud clearing algorithm). The daily data consist of statistical summaries of each 10 X 10 degree latitude/longitude box. The Office of Satellite Data Processing and Distribution (OSDPC) keeps this data for a month, then sends it to the National Climatic Data Center (NCDC) for archiving. For current data, contact John Sapper at OSDPC, telephone 301-457-0914 ext.148, e-mail: john.sapper@noaa.gov. For archived data contact Thomas Ross at NCDC, telephone 828-271-4499, e-mail: tom.ross@noaa.gov.

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    Variable Name (Sampling): Zonal Wind (JFM Mean at 300 hPa) ID: 11 Region: N. Pacific: 60N,180E Data Type: Atmosphere Units: m/s Lon.:180E Lat.: 60N Start Year: 1948 End Year: 1999

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    No abstract was givien, contact provider for more information

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    Delegates from more than 100 countries met in Shanghai, China, this week, and approved a United Nations report that for the first time places the blame for climate warming squarely on the burning of fossil fuels. As Doug Schneider reports in this week's Arctic Science Journeys Radio, scientists believe global warming will have a particularly profound effect on the Arctic.