Spatial temporal variability of free atmosphere in the Arctic in 1950s 1990s

1
 Spatial - temporal variability of free
atmosphere in the Arctic in 1950s 1990s A.P.
Makshtas, International Arctic Research Center,
University of Alaska Fairbanks V.V. Maistrova,
Arctic and Antarctic Research Institute, St.
Petersburg, Russia
Starting 2000 Arctic and Antarctic Research
Institute (Russia) and International Arctic
Research Center (USA) execute the project
Climate variability of the polar atmosphere
revealed with historical radio soundings
information. This project is an joint effort to
create with unified modern technique the new data
set of the radio soundings, executed north of 650
N on the Russian coastal (island) polar stations
and drifting stations North Pole. The data of
67 polar stations, 9 of which had begun
observations in the middle 30s will be prepared.
Together with existent archives of soundings from
US, Canada, Norway, Denmark, and some Russian
polar stations, collected in the Comprehensive
Aerological Reference Data Set (CARDS), and
improved archive of the drifting stations "North
Pole", the new data set will give possibility to
reveal the seasonal and interannual variability
as well as the trends of main parameters of the
troposphere, stratosphere, atmospheric boundary
layer, and cloudiness and to obtain the new
estimations of energy and moisture fluxes across
700 N. Below we present the preliminary results
of investigations the climate of the polar
atmosphere, based on the new version of drifting
stations North Pole dataset, original database
of monthly averaged sounding data created in
AARI, and long-term series of observations
executed on the polar station Dickson in
1935-2002.
Characteristics of low-level inversions in the
Central Arctic based on observations of the
drifting stations North Pole

 
DATABASE AARI  The original database of monthly
averaged sounding data, covered the period
1958-2001, had been was created by collection the
results of soundings executed on 116 polar
stations, research vessels and drifting stations
"North Pole". The data of regular twice-daily
observations had been collected starting in 1978
from the Global Communications System. For the
earlier period, the specialized archives of AARI
together with Archive of the Russian State
Research Institute of Hydrometeorological
Information and Historical Arctic Rawinsonde
Archive (Kahl et al, 1992) had been utilized. As
a considerable part of the data had been obtained
from the moving platforms (drifting stations and
research vessels) the original method the
generalization of the sounding information had
been applied. There were selected 36 climatic
homogeneous oceanic regions in the North Polar
Region (NPR). The information obtained in a
specified region of the ocean during each month
had been interpolated in the center of the region
with the special procedure. Taken into account
that the quantity of the sounding data for ocean
regions is essential less than for polar
stations, the time series of the data for these
regions were supplemented by the data obtained as
a result of the synoptic analysis.
 
 
The location of sounding stations in the Northern
Polar Region and grid, applied in database. ? -
sounding station, ? - centers of areas where data
from moving platforms had been used.
 
 
Trends of the annual mean air temperature in the
polar atmosphere for 1959-2001 (C/10 years).
Trends of the annual mean specific humidity in
the polar atmosphere for 1959-2001 (g/kg/10
years).
Spatial distributions of air temperature and
specific humidity trends in NPR. The spatial
distributions of the air temperature trends in
NPR have inhomogeneous and complicated character.
In the lower troposphere (850 hPa), the air
temperature above the Arctic Ocean strongly
increased. It is an important feature of climatic
change in the Central Arctic, because the level
850 hPa is the closest to the upper boundary of
the atmospheric boundary layer and in great
degree determines the air surface layer
temperature. At the same time, a well-pronounced
decrease of air temperature on the 50 hPa,
especially in the European part of NPR. It could
be connected with increasing of total ozone
depletion events. The spatial distributions of
the specific humidity trends show its increase in
the Canadian Arctic and mainly decrease in the
Eurasian Arctic. Such spatial inhomogenity could
determine the changes in radiation regime of
different Arctic regions.
 
Time series of annual mean temperature and
specific humidity anomalies normalized on mean
square deviation in the polar atmosphere for
1959-2001

Temporal variations of annual mean temperature
and specific humidity in polar atmosphere During
1959-2001 the annual mean air temperature in the
low troposphere (850 - 500 hPa) averaged over
whole NPR had increased and the temperature of
the upper troposphere (higher 400 hPa) as well as
the stratosphere had decreased. Same time the air
temperature variations on 400 hPa, so called
mean energetic level, where the values of
potential energy gH400 and enthalpy RT400 are
almost the same and roughly equal to the
vertically average potential energy and enthalpy
of the whole atmospheric column, do not reveal
any trends. It is possible to assume that strong
temporal variations of air temperature in this
layer connect with macrocirculation processes of
the global atmosphere. Annual mean specific
humidity had increased only in low troposphere
(up to 850 hPa) and had decreased above this
height.
c
d
b
a
Temporal variability of air temperature (a),
humidity (b), wind velocity (c) and geopotential
heights (d) in 1935 2002 years from
radiosoundings on Dickson

• Preliminary results and future plans
• The longest dataset of radiosoundings from the
  polar station Dickson shows remarkable difference
  of polar atmosphere in 1930s compare to present
  the whole investigated part of atmosphere had
  been warmer and higher, and the intensity of
  surface-based inversion had been lower and its
  height was higher. The last could be due to
  decrease the radiation cooling of surface related
  with warming of whole atmosphere as well due to
  changes in cloudiness.
• In future we plan
• to create the final version of historical dataset
  of the radio soundings, including data of
  soundings, executed on coastal and island polar
  stations in 1930s
• To develop procedure for homogenization of data
  row, combined with data obtained with different
  sensors
• to made comprehensive statistical analysis of
  spatial-temporal variability of the main
  characteristics of free atmosphere, including
  Wavelet and EOF analysis
• to develop the modern parameterization of the
  atmospheric boundary layer accounting existence
  of low level inversions and to investigate
  long-term variability of surface fluxes in the
  area under study
• to estimate energy and water vapor exchange with
  middle latitudes under different peculiarities of
  atmospheric circulation.

Long-term variability of surface-based inversion
layer from radiosoundings on the Dickson Island.
a, b wind velocity and humidity on the upper
boundary of inversion , c inversion height, d-
intensity of inversion.