Atmospheric circulation patterns and geochemistry time series from ice/firn cores and snow samples of central Asian glaciers (Pamir, Tien Shan and Altai).
Abstract
Combination of high mountain ice-core isotope-geochemistry, ground based aerosol monitoring, NASA remote sensed and a NOAA atmospheric pressure distribution data were used to receive information on sources of dust/loess transport, their time and spatial extension in modern and pre-industrial time. Hundreds of samples from snow pits and ice/firn cores obtained from central Asian glaciers were collected, processed and analyzed. The NASA RS products address the gap in interpretation of available snow, firn and ice records by providing the spatial resolution necessary for identifying possible local and regional-scale dust sources, transport routes and depositions. NOAA Hypslit program modeled the air back-trajectories allowed to found association between the ice core geochemistry records and aerosol sources. To find the circulation patterns, which are closely associated with geochemistry ice core/snow pit records, the correlation coefficients between the Empirical Orthogonal Functions of the atmospheric circulation patterns and geochemistry time coefficients for first two unrotated scores were computed. The loess / dust storm sources with corresponding geo-chemical composition (trace elements, major ions and dust particles) in western, central and northern Asia were identified: 1. Tajik loess deposition and Iran, Afghanistan /Turkmenistan sands are for the Pamir. For example, the Pamir ice core records that associated with Tajikistan loess deposition are characterized by high concentrations of REEs and Al, high or median content of Ca, and a background S concentration. Samples from the Pamir Mountains differed in having low concentrations of Gadolinium. Occasional intrusions of Chinese loess to Pamir glaciers are not excluded. REE profile of pilot Pamir cores documented one of the most extreme droughts of 2001 and 2002 that developed in south-west Asia. 2. Chinese loess deposition in the Takla Makhan, sands in the Tajikistan Deserts and western Gobi, and dust aerosols from Aral region are for the Tien Shan; 3. Western and central Gobi and Kazakhstan dust are for the Altai. The Aral region is the source of dust aerosol for Altai also. Based on in-situ data in the western Central Asia and Altai ice core records of particle number content there is tendency on decrease of dust storms frequency from the 30th in central and eastern Asia.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP13A1427A
- Keywords:
-
- 0305 Aerosols and particles (0345;
- 4801;
- 4906);
- 0454 Isotopic composition and chemistry (1041;
- 4870);
- 0724 Ice cores (4932);
- 3305 Climate change and variability (1616;
- 1635;
- 3309;
- 4215;
- 4513);
- 3344 Paleoclimatology (0473;
- 4900)