Chiyuki Narama

Recent changes of glacier coverage in the western Terskey-Alatoo range, Kyrgyz Republic, using Corona and Landsat

Abstract Corona images from 1971 and a Landsat image from 2002 are used to assess glacier variations in the last 30 years in the western Terskey-Alatoo range (a part of the Tien Shan), in the northeast of the Kyrgyz Republic. The glaciers have shrunk during this period. The 269 mountain glaciers measured in the study area had an original combined area of 245 km2, which has decreased 18.4 km2, representing a loss of 8% of the original glacier coverage in 1971. Individual glaciers covering <1km2 account for 28% of the combined glacial coverage, but loss from these small glaciers represents 38% of the total decrease in area. The relative change of area is larger for small-scale glaciers, and its contribution to shrinkage of glacier area is high. This shrinkage has been linked to climate changes as recorded at local stations. Many small-scale glaciers are distributed around Issyk-Kul lake, and rapid glacier reduction is expected in this area in the future.

Glacial lake inventory of Bhutan using ALOS data: methods and preliminary results

Abstarct The Advanced Land Observing Satellite (ALOS) is relatively new. Its optical sensors are capable of making high-resolution digital surface models (DSMs). For the first time, the task of constructing a regional-scale inventory of glacial lakes based on ALOS data has been undertaken. This study presents the data-processing methods and the results of validation and analysis on the ALOS-based glacial lake inventory of Bhutan in the Himalaya. The analysis based on GPS measurements taken at Metatshota lake in the Mangde Chu sub-basin, one of the glacial lakes assessed as presenting a potential flood danger, shows a validation estimate of 9.5 m for the location of the ALOS-based polygon, with a root mean square of 11.7 m. A comparison with digitized data from the International Centre for Integrated Mountain Development (ICIMOD) shows that positioning and evaluation of terrain changes can be significantly improved using ALOS data. Preliminary analysis of the glacial lakes in four sub-basins, Mo Chu, Pho Chu, Mangde Chu and Dangme Chu, reveals that the frequency distribution of lake sizes biases towards smaller lakes. Glacial lakes 0.01–0.05km2 in area account for ~55% of the total number and occupy 13% of the total area. Together our results demonstrate the usefulness of high-resolution ALOS data with accurate DSMs for studying glacial lakes. High priority must be given to continuously improving and updating the glacial lake inventory with high-resolution satellite data.

Record of glacier variations during the last glacial in the Turkestan range of the Pamir-Alay, Kyrgyz Republic

Abstract Moraines in five valleys of the Turkestan range of the Pamir-Alay, Kyrgyz Republic, were analyzed based on their geographical position and elevation, morphology and ecological characteristics. The moraines represent four glacial advances: Turkestan Stage I, during the last glacial; Stage II, during the late Holocene; Stage III, during the Little Ice Age (AD 1400−1900); and Stage IV, during the 20th century. In Turkestan Stage I, the glaciers expanded to about 5−10 km from their present termini during marine isotope stage (MIS) 2. Radiocarbon ages for several soil layers buried in a lateral moraine of the Asan-Usin glacier frontal area indicate that glaciers shrank or stagnated between at least ∼48 and 42 kyr BP, during the warm climate of mid-MIS 3. These findings suggest that the glacier expansion in mid-MIS 3 was relatively small compared to the glacier expansion of MIS 2 during the last glacial.

Variations in discharge from the Qilian mountains, northwest China, and its effect on the agricultural communities of the Heihe basin, over the last two millennia

Over the last two millennia, agricultural land in the Hei river basin, northwest China, has been subjected to a series of significant droughts and flood events. These documented hydrological events were compared to estimates of fluvial and fluvioglacial discharge from the mountains. Areal extents of glaciers are important for validation as water mass remaining in mountain area, although glacier area occupied only about 1.5 % at present in this high mountain area. These glacier mass balance and discharge estimates, calculated using proxy data, appear reasonable, as the total maximum glacier area during the little ice age (LIA) was comparable to the maximum glacier area deduced from the positions of terminal moraines. The precise timing of the glacier area maximum during the LIA in the Qilian mountains is unknown. However, variations in the calculated glacier area suggest that glacier extent reached a maximum between 1520 and 1690 CE. A number of the historical drought events occurred during periods of reduced discharge from the mountains, and, conversely, flood events tended to coincide with an increase in discharge from glaciers. Historical documents record five multi-year droughts in the basin between 1200 and 2000 CE. The modelling of the fluctuating pattern of fluvial and fluvioglacial discharge implies that at least two drought events were anthropogenically driven. Furthermore the reasons for the presence or absence of drought events are considered based on continuous discharge fluctuation and water demands of each ages, that can be estimated from analysing intermittent historical documents.

Development of glacial lake inventory in Bhutan using “Daichi” (ALOS)

The objective of this study is to develop new glacial lake inventory to understand existing condition using the optical imageries of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) onboard the Advanced Land Observing Satellite (ALOS, nicknamed “Daichi”). Glacial lakes can be caused outburst flood when natural dams terminated by moraines are broken, and it represents serious hazard damage in downstream regions. Problems of glacial lake outburst floods (GLOFs) are that anyone does not know when it will occur and how much damage causes by it. To contribute these problems, new glacial lake inventory is currently developing in the Bhutan Himalayan using ALOS imageries. This paper describes procedure of the inventory development including image processing that introduces pan-sharpened and ortho-rectified images by PRISM and AVNIR-2, glacial lakes extraction, and its validation.

Knowledge Sharing for Disaster Risk Reduction: Insights from a Glacier Lake Workshop in the Ladakh Region, Indian Himalayas

Small glacier lakes are distributed in the Ladakh Range in northwestern India. This area has experienced several glacier lake outburst floods (GLOFs) since the 1970s, damaging settlements along streams. To reduce GLOF risk through a knowledge-based approach focused on nonstructural measures, we held a workshop in May 2012 for residents of Domkhar Village in the northwestern part of the Ladakh Range. More than 100 villagers participated in the workshop, which conveyed useful disaster information to participants while enabling the researchers to understand local knowledge and beliefs about floods. A survey conducted 3 months later confirmed an improvement in residents’ knowledge of natural disasters. The researchers also learned useful lessons, such as the need to adjust the program design for diverse participants and the importance of clearly communicating disaster risks and supporting local residents’ attempts to incorporate new scientific knowledge into existing local knowledge. Challenges to implementing flood countermeasures in this area included problems relating to land use and emergency communications and the need for coordination of efforts by the government and local residents.