Prefaces Acknowledgements 1. Mountains and their climatological study 2. Geographical controls of mountain meteorological elements 3. Circulation systems related to orography 4. Climatic characteristics of mountains 5. Regional case studies 6. Mountain bioclimatology 7. Changes in mountain climates Appendix General index Author index.

Mountain Weather and Climate

We present a comprehensive review of the status and changes in glacier length (since the 1850s), area and mass (since the 1960s) along the Himalayan-Karakoram (HK) region and their climate-change context. A quantitative reliability classification of the field-based mass-balance series is developed. Glaciological mass balances agree better with remotely sensed balances when we make an objective, systematic exclusion of likely flawed mass-balance series. The Himalayan mean glaciological mass budget was similar to the global average until 2000, and likely less negative after 2000. Mass wastage in the Himalaya resulted in increasing debris cover, the growth of glacial lakes and possibly decreasing ice velocities. Geodetic measurements indicate nearly balanced mass budgets for Karakoram glaciers since the 1970s, consistent with the unchanged extent of supraglacial debris-cover. Himalayan glaciers seem to be sensitive to precipitation partly through the albedo feedback on the short-wave radiation balance. Melt contributions from HK glaciers should increase until 2050 and then decrease, though a wide range of present-day area and volume estimates propagates large uncertainties in the future runoff. This review reflects an increasing understanding of HK glaciers and highlights the remaining challenges.

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Review of the status and mass changes of Himalayan-Karakoram glaciers

The cryosphere is defined by the presence of frozen water in its many forms: glaciers, ice caps, ice sheets, snow, permafrost, and river and lake ice. In the extended Hindu Kush Himalaya (HKH) region, including the Pamirs, Tien Shan and Alatua, the cryosphere is a key freshwater resource, playing a vital and significant role in local and regional hydrology and ecology. Industry, agriculture, and hydroelectric power generation rely on timely and sufficient delivery of water in major river systems; changes in the cryospheric system may thus pose challenges for disaster risk reduction in the extended HKH region.

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Status and change of the cryosphere in the Extended Hindu Kush Himalaya Region

. In the Everest region, Nepal, ground-based monitoring programmes were started on the debris-free Mera Glacier (27.7° N, 86.9° E; 5.1 km2, 6420 to 4940 m a.s.l.) in 2007 and on the small Pokalde Glacier (27.9° N, 86.8° E; 0.1 km2, 5690 to 5430 m a.s.l., ~ 25 km north of Mera Glacier) in 2009. These glaciers lie on the southern flank of the central Himalaya under the direct influence of the Indian monsoon and receive more than 80% of their annual precipitation in summer (June to September). Despite a large inter-annual variability with glacier-wide mass balances ranging from −0.67 ± 0.28 m w.e. in 2011–2012 (Equilibrium-line altitude (ELA) at ~ 5800 m a.s.l.) to +0.46 ± 0.28 m w.e. in 2010–2011 (ELA at ~ 5340 m a.s.l.), Mera Glacier has been shrinking at a moderate mass balance rate of −0.08 ± 0.28 m w.e. yr−1 since 2007. Ice fluxes measured at two distinct transverse cross sections at ~ 5350 m a.s.l. and ~ 5520 m a.s.l. confirm that the mean state of this glacier over the last one or two decades corresponds to a limited mass loss, in agreement with remotely-sensed region-wide mass balances of the Everest area. Seasonal mass balance measurements show that ablation and accumulation are concomitant in summer which in turn is the key season controlling the annual glacier-wide mass balance. Unexpectedly, ablation occurs at all elevations in winter due to wind erosion and sublimation, with remobilised snow potentially being sublimated in the atmosphere. Between 2009 and 2012, the small Pokalde Glacier lost mass more rapidly than Mera Glacier with respective mean glacier-wide mass balances of −0.72 and −0.23 ± 0.28 m w.e. yr−1. Low-elevation glaciers, such as Pokalde Glacier, have been usually preferred for in-situ observations in Nepal and more generally in the Himalayas, which may explain why compilations of ground-based mass balances are biased toward negative values compared with the regional mean under the present-day climate.

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Seasonal and annual mass balances of Mera and Pokalde glaciers (Nepal Himalaya) since 2007

. In this study, we apply a glacier mass balance and ice redistribution model to examine the sensitivity of glaciers in the Everest region of Nepal to climate change. High-resolution temperature and precipitation fields derived from gridded station data, and bias-corrected with independent station observations, are used to drive the historical model from 1961 to 2007. The model is calibrated against geodetically derived estimates of net glacier mass change from 1992 to 2008, termini position of four large glaciers at the end of the calibration period, average velocities observed on selected debris-covered glaciers, and total glacierized area. We integrate field-based observations of glacier mass balance and ice thickness with remotely sensed observations of decadal glacier change to validate the model. Between 1961 and 2007, the mean modelled volume change over the Dudh Koshi basin is −6.4 ± 1.5 km3, a decrease of 15.6% from the original estimated ice volume in 1961. Modelled glacier area change between 1961 and 2007 is −101.0 ± 11.4 km2, a decrease of approximately 20% from the initial extent. The modelled glacier sensitivity to future climate change is high. Application of temperature and precipitation anomalies from warm/dry and wet/cold end-members of the CMIP5 RCP4.5 and RCP8.5 ensemble results in sustained mass loss from glaciers in the Everest region through the 21st century.

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Modelling glacier change in the Everest region, Nepal Himalaya

This paper provides the results of hydrological modelling in a mesoscale glaciated alpine catchment of the Himalayan region. In the context of global climate change, the hydrological regime of an alpine mountain is likely to be affected, which might produce serious implications for downstream water availability. The main objective of this study was to understand the hydrological system dynamics of a glaciated catchment, the Dudh Kosi River basin, in Nepal, using the J2000 hydrological model and thereby understand how the rise in air temperature will affect the hydrological processes. The model is able to reproduce the overall hydrological dynamics quite well with an efficiency result of Nash–Sutcliffe (0.85), logarithm Nash–Sutcliffe (0.93) and coefficient of determination (0.85) for the study period. The average contribution from glacier areas to total streamflow is estimated to be 17%, and snowmelt (other than from glacier areas) accounts for another 17%. This indicates the significance of the snow and glacier runoff in the Himalayan region. The hypothetical rise in temperature scenarios at a rate of +2 and +4 °C indicated that the snowmelt process might be largely affected. An increase in snowmelt volume is noted during the premonsoon period, whereas the contribution during the monsoon season is significantly decreased. This occurs mainly because the rise in temperature will shift the snowline up to areas of higher altitude and thereby reduce the snow storage capacity of the basin. This indicates that the region is particularly vulnerable to global climate change and the associated risk of decreasing water availability to downstream areas. Under the assumed warming scenarios, it is likely that in the future, the river might shift from a ‘melt-dominated river’ to a ‘rain-dominated river’. The J2000 model should be considered a promising tool to better understand the hydrological dynamics in alpine mountain catchments of the Himalayan region. This understanding will be quite useful for further analysis of ‘what-if scenarios’ in the context of global climate and land-use changes and ultimately for sustainable Integrated Water Resources Management in the Himalayan region. Copyright © 2012 John Wiley & Sons, Ltd.

Understanding the hydrological system dynamics of a glaciated alpine catchment in the Himalayan region using the J2000 hydrological model

Unlike to so called lumped models in which the quantification of several processes results from a statistical relation between system input and system output for the whole catchment, distributed models enable the differentiation of single modelling entities (e.g. Hydrological Response Units - HRU) which can be parameterized and modelled independently. Furthermore spatially distributed hydrological modelling requires a topological linkage of several entities in order to reproduce relevant attenuation and translation processes within the stream but also during the transport of water in form of lateral surface or subsurface flow. Most often such linkage is considered by a one dimensional (1D) approach which links one modelling entity to only one receiver that follows in flow direction. The comparison with actual lateral water movement in catchments show that such a 1D routing scheme is often too simple which can lead to an overestimation of the runoff concentration along the 1D flow paths. On the other hand an underestimation of runoff in flow cascades that do not reside next to the main 1D flow paths can occur as the affected HRUs don't receive realistic inflow from their source entities above. As a catchment-wide consequence the 1D routing scheme can result in a significant over- or underestimation of the contributing area for specific parts of a catchment which can have important implications on the spatial distribution of accompanying processes such as spatial variation of soil moisture, soil erosion or solute transport. For example by modelling soil erosion, the one dimensional approaches show functional weaknesses because of the overestimation of rill erosion along the 1D flow paths. To address the problems outlined above a new two-level approach has been developed that allows a multi- dimensional linkage of model entities in such a way that each entity can have various receivers to which the water is passed. On the first level the neighbourhood relations between the model entities are quantified. The area of a HRU which contributes to the runoff to one of its neighbours is compared to the overall contribution area of the same HRU. As a result a fraction of the entire runoff can be assigned to every flow relation. In a second step, an exact analysis of the flow cascades is conducted to identify so-called circle flows, in which the runoff of a HRU flows back to the same HRU. Throughout the model run, the runoff of the HRUs involved in a circle flow is not routed to catchments outlet. The improved routing method introduces a new approach for the elimination of circle flows by modifying certain flow relations without altering the whole topology abundantly. This extended routing scheme was implemented in the hydrological modelling system J2000 and was used for the simulation of the hydrological processes of a number of meso-scaled catchments in Thuringia, Germany. The paper will present the most important facts of the extended routing scheme, the first simulation results along with the comparison of those obtained with the 1D linkage and will highlight the impacts on the hydrological process dynamics.

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Development of an extended routing scheme in reference to consideration of multi-dimensional flow relations between hydrological model entities

W artykule przedstawiono opracowany na Uniwersytecie w Jenie pakiet oprogramowania RBIS (River Basin Information System). Umozliwia on z poziomu przeglądarki internetowej zarządzanie danymi roznego typu (w tym danymi przestrzennymi), ich integracje, wizualizacje, analizowanie oraz wymiane z innymi systemami. Pakiet pomyślany zostal jako integralna calośc mogąca funkcjonowac samodzielnie bądź stanowic element pakietu ILMS (Integrated Landscape Management System, Zintegrowany System Zarządzania Krajobrazem) wspomagającego proces zintegrowanego zarządzania obszarem zlewni. W pracy zaprezentowano zarowno architekture systemu jak i jego funkcjonalnośc oraz korzyści plynące z jego wykorzystania w ramach zintegrowanego zarządzania obszarem zlewni, rozumianego jako holistyczny proces planowania środowiskowego. Przedstawiono rowniez mozliwości wykorzystania w procesie budowy systemu RBIS danych przestrzennych dostepnych w ramach polskiej Infrastruktury Informacji Przestrzennej. Źrodla danych dla tego rodzaju systemu omowiono na przykladzie implementacji realizowanej dla zlewni Zbiornika Dobczyckiego w ramach projektu SaLMaR (Sustainable land and Water management of Reservoir Catchments).

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W. A. Flügel

Papers

Understanding the hydrological system dynamics of a glaciated alpine catchment in the Himalayan region using the J2000 hydrological model

Development of an extended routing scheme in reference to consideration of multi-dimensional flow relations between hydrological model entities

Krajowa infrastruktura informacji przestrzennej jako źródło danych dla Systemu Informacji o Zlewni (RBIS)