Head Shot Research

Science Research on Central Asia

I did my research paper on drought records for Central Asia using tree rings. Central Asia drought has had drastic impacts on vast regions over recent years. Mongolia is representative of the Central Asian region and tree ring resources are used to extend the climate record and they are used to test for solar influence and Pacific Ocean teleconnections (Davaa, 2003). Mongolia was hit hard with four years of extensive drought; studies demonstrated that tree ring analysis can be used to reconstruct precipitation and stream flow in Eastern Mongolia. The stream flow of the Kherlen River was reconstructed back to 1651.

     The precipitation models and stream flow reconstruction presented and based on annual ring-width variations of moisture-stressed, old aged trees. The tree ring data was tested against regional averages of precipitation for the central region of Mongolia  (Hereford, 1995). There was a tree ring record that went all the way back 360 years for the stream flow variations of the Selenge River. Standard tree-ring methods were used for chronology development and climate analysis. Some ways to measure ring widths is using a velmex system, individual series measurements and dating can be found by using COFECHA software and ARSTAN software. The purpose of standardization is to cut down the effects of age and non-climatic factors. In the hydrological data section of this article states that most stream flow discharge would occur in July and August, spring stream flow comes from melting winter snowpack.

     Each individual chronology was tested with Selenge stream flow data for current and prior year. Three of the five chronologies show correlations with prior year stream flow, most stream flow models using tree ring data are linear; in some different situations they can be non-linear too. With increasing amounts of precipitation, levels are reached that do not cause ring widths to increase at the same rate that they do for the increases at lower levels; trees go through other growth restraints like nutrient supply and internal biochemical limitations  (Morinaga, 2003). Stream flow can be a better indicator of regional water resources than individual station precipitation records. Stream flow integrates the effects of precipitation input, and the earlier precipitation directly benefits the tree growth. The reconstruction extends beyond the season of cambial (ring) growth to better represent the longer season of stream flow, and the longer season of biological activity, April-October  (Davaa, 2003). In the conclusion of this summary it talks about bow this reconstruction is a reliable record of the Selenge river stream flow in West-Central Mongolia and it increases the knowledge of drought periods  (Hereford, 1995). There is a much larger variation in the long term ring record than in the limited record of precipitations.

References

Davaa, G. (2003). Hydrological regime analysis of the Selenge River basin, Mongolia. Proquest, 2929-2945.

               Hereford, R. (1995). Geomorphic history of the Virgin River in the Zion National Park area, Southwest Utah. Proquest, 75.

               Morinaga, Y. (2003). Winter Snow Anomaly and Atmospheric Circulation in Mongolia. Proquest, 1627.