Research: monitoring

Monitoring climate, permafrost and stream hydrology
Researchers: Dr. Clyde Goulden, Dr. Brent Helliker

It is important to continue monitoring permafrost conditions because elevated soil moisture is associated with the presence of permafrost. Northern Mongolia and the Hövsgöl region represent the southern limit of the Siberian continuous permafrost zone, and the ILTER site at Lake Hövsgöl is part of the Circumpolar Active Layer Monitoring (CALM) program. Data collected since the early 1980s indicate an increase in active layer thickness from 3 to 25 cm per decade, and an increase in the annual permafrost temperature from 0.2°C to 0.4°C per decade, depending on local landscape and ground conditions. Long-term monitoring shows that permafrost is degrading more intensively during the last 15 years than during the 1970-1980s.

During the GEF project, fifteen 10-meter deep boreholes spread over the six valleys at the ILTER site were used to monitor permafrost temperatures and active layer depths, and we are continuing the monitoring of the GEF boreholes and in other nearby much deeper boreholes monitored since the early 1980s. Sharkhuu, who worked on the GEF project, is helping with the permafrost measurements. The boreholes are cased in steel and plastic with the top of the bore 15-20 cm below the surface. Temperatures are measured using thermistors with an accuracy of ±0.1°C.

We are monitoring meteorological conditions at Hatgal at the southern edge of Lake Hövsgöl by a combination of traditional techniques and by a Campbell CR10X station. Conditions at Hatgal are similar to the ILTER field site. Data are collected every four hours, and include PAR (photosynthetically active radiation), air and ground temperature, soil moisture, wind direction and speed, precipitation and relative humidity. These data are archived by the Meteorological Institute of the Ministry of Nature and Environment in Mongolia.

Stream water hydrology and chemistry are modified by climate warming of the region, largely due to permafrost thaw and increased evapotranspiration associated with the longer growing season, and so it is important to continue monitoring these conditions. Similar hydrology methods as in the GEF project are being used, but with improved pressure transducers. These are installed in late spring each year in perforated stand pipes, as the stream ice melts and monitoring continues throughout the summer and autumn until the streams begin to freeze. Frequent water depths and flow measurements are made to relate stream flow to water level by cross-section measurements of each stream under different flow regimes.

Stream grab samples are collected each year in June, July and August at three elevations in each of the six major catchments draining into Lake Hövsgöl. Water temperature, pH, conductivity, alkalinity and hardness, and dissolved oxygen are determined in the field using portable thermistors, pH and DO meters, and standardized titration techniques. Samples are also returned to Ulaanbaatar for further analysis at MUST and SUNY-ESF. Variables measured at MUST and SUNY-ESF include: (1) major anions (SO42-, NO3-, Cl-) via ion chromatography, (2) major cations (Ca2+, Mg2+, Na+, K+) with ICPOES (Inductively Coupled Plasma-Optical Emission Spectrophotometer), (3) DOC with a TOC analyzer, (4) total dissolved nitrogen (TDN) via persulfate oxidation with an Auto Analyzer 3 and (5) dissolved organic N (DON) by subtracting NH4-N (determined by Auto Analyzer) and NO3-N concentrations from TDN.

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