Temperature lapse rate in complex mountain terrain on the southern slope of the central Himalayas

Global warming is triggering some species to shift towards the poles or higher elevations, but spatial translocation is also influenced by land-use regime or intensity. The Himalayan climate is getting warmer and land use has changed, reducing in intensity in some areas. We estimated the upper species limit (USL) and tree limit of Abies spectabilis (D. Don) Spach and assessed whether these have changed over recent years. We hypothesise an upslope shift in response to enhanced temperature and changes in land-use intensity. Our four transects were located in treeline ecotones of two protected areas in Nepal, namely Manaslu Conservation Area (3 transects) and Gaurishankar Conservation Area (1 transect). Transects (20 m wide) ran from the USL of A. spectabilis down towards the treeline and beyond to the forest line. Length of each transect varied depending on local conditions. Co-ordinates, elevation, height and age of each A. spectabilis individual along the transects were recorded. We noted an upward shift of both the USL and the tree limit. The rate of shift was ca. 20 m per decade for the USL and 12 m per decade for the tree limit in the area of reduced land-use intensity and in the area with no change in land use, 5 m per decade for the USL, but almost nil for tree limit. The seedling density was higher below the treeline than above. Reduced intensity of land use was the dominant factor in upslope shift of A. spectabilis at both the USL and the tree limit.

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“…We used available climate data (Kattel et al 2013). Temperature has been increasing at a rate of ca.…”

Section: Climatementioning

confidence: 99%

Land-use change under a warming climate facilitated upslope expansion of Himalayan silver fir (Abies spectabilis (D. Don) Spach)

Suwal

Shrestha²,

Guragain³

et al. 2016

Plant Ecol

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“…The observed monthly mean lapse rates vary from 0.05C/100 m for September to 1.4C/100 m for March. The lower values of lapse rate during August and September can be explained by the increased moisture content in the atmosphere during monsoon season 15,20 . The higher lapse rate in March corresponds to the pre-monsoon (summer) season associated with clear weather and significant sensible heat flux 20 .…”

Section: Resultsmentioning

confidence: 99%

“…The lower values of lapse rate during August and September can be explained by the increased moisture content in the atmosphere during monsoon season 15,20 . The higher lapse rate in March corresponds to the pre-monsoon (summer) season associated with clear weather and significant sensible heat flux 20 . Following this, the implications of this observed variability of LR for hydrological modelling using SRM have been analysed.…”

Section: Resultsmentioning

confidence: 99%

“…Minder et al 14 studied such an implication for Cascade Mountains (Washington), where they found that the lapse rates in that region substantially differed from the constant value and had appreciable implications to hydrological modelling. Kattel et al 20 looked into the nearsurface lapse rate variation on the southern slope of the central Himalayas and found that there was a temporal variation associated with the annual cycle of temperature lapse rates. Such a variation over a year is found to be a characteristic of Himalayas and is different from other mountainous regions 20 .…”

Section: Introductionmentioning

confidence: 99%

“…Kattel et al 20 looked into the nearsurface lapse rate variation on the southern slope of the central Himalayas and found that there was a temporal variation associated with the annual cycle of temperature lapse rates. Such a variation over a year is found to be a characteristic of Himalayas and is different from other mountainous regions 20 . Considering the unique characteristics of annual lapse rate in Himalayan region, it is necessary to understand its implication in terms of parametrization while performing snowmelt related hydrological simulations of Himalayas.…”

Section: Introductionmentioning

confidence: 99%

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Investigating the Performance of Snowmelt Runoff Model Using Temporally Varying Near-Surface Lapse Rate in Western Himalayas

Kulshrestha¹,

Ramsankaran²,

Kumar³

et al. 2018

Current Science

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The present study assesses the effect of accounting the temporal variation of near-surface lapse rate in the conceptual, degree-day snowmelt runoff model simulations in a cold-desert region of Himalayas. The nearsurface lapse rate over Spiti basin shows seasonal variation during a year. The results obtained show that the inclusion of monthly variation of lapse rate in the hydrological modelling is able to capture the observed hydrograph more efficiently than when an annually constant value of lapse rate is employed. Based on our results and considering the available data, a monthly representation of near-surface lapse rates in the temperature index based models is recommended for Himalayan basins.

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The importance of observed gradients of air temperature and precipitation for modeling runoff from a glacierized watershed in the Nepalese Himalayas

Immerzeel

Petersen

Ragettli

et al. 2014

Water Resources Research

244

281

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The performance of glaciohydrological models which simulate catchment response to climate variability depends to a large degree on the data used to force the models. The forcing data become increasingly important in high-elevation, glacierized catchments where the interplay between extreme topography, climate, and the cryosphere is complex. It is challenging to generate a reliable forcing data set that captures this spatial heterogeneity. In this paper, we analyze the results of a 1 year field campaign focusing on air temperature and precipitation observations in the Langtang valley in the Nepalese Himalayas. We use the observed time series to characterize both temperature lapse rates (LRs) and precipitation gradients (PGs). We study their spatial and temporal variability, and we attempt to identify possible controlling factors. We show that very clear LRs exist in the valley and that there are strong seasonal differences related to the water vapor content in the atmosphere. Results also show that the LRs are generally shallower than the commonly used environmental lapse rates. The analysis of the precipitation observations reveals that there is great variability in precipitation over short horizontal distances. A uniform valley wide PG cannot be established, and several scale-dependent mechanisms may explain our observations. We complete our analysis by showing the impact of the observed LRs and PGs on the outputs of the TOPKAPI-ETH glaciohydrological model. We conclude that LRs and PGs have a very large impact on the water balance composition and that short-term monitoring campaigns have the potential to improve model quality considerably.

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Temperature lapse rate in complex mountain terrain on the southern slope of the central Himalayas

Cited by 185 publications

References 32 publications

Land-use change under a warming climate facilitated upslope expansion of Himalayan silver fir (Abies spectabilis (D. Don) Spach)

Land-use change under a warming climate facilitated upslope expansion of Himalayan silver fir (Abies spectabilis (D. Don) Spach)

Investigating the Performance of Snowmelt Runoff Model Using Temporally Varying Near-Surface Lapse Rate in Western Himalayas

The importance of observed gradients of air temperature and precipitation for modeling runoff from a glacierized watershed in the Nepalese Himalayas

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