Does the climate high elevation along the Mt Everest can be represented by lower elevation stations?

Climate change/ impact studies depend on the in-situ meteorological data directly or indirectly. Due to the lack of meteorological stations in the high altitude, the climate of the Himalayan region is always represented by the meteorological stations in the lower elevation, generally at the valley bottom. Therefore, in order to validate the climatic linkages from lower to the higher elevation we examine daily observational climate data for a decade at five automated weather stations (AWS) in different elevations, ranging from 2660 m a.s.l. to 5600 m a.s.l., on the southern side of the Mt Everest at the Central Himalaya.

We found the variation in the means and distribution of daily, 5-day, 10-day, and monthly average/sum of temperature/precipitation between the stations in the different elevation. Despite these the differences, the temperatures records are consistent in the different station in the corresponding altitudes and highly correlated to each other except station at snow covering areas with snow-free areas while the precipitation data shows comparatively weaker correlation.

The slopes of the regression model (0.82-1.13) with (R2>0.74) for higher altitude (5050m asl and 5600m asl) throughout the year, 0.83-1.12 (R2 >0.68) except July, August, September, October ( late monsoon season) for station at 4260 ma sl and 5050 m sl indicate the similar variability of the temperature between those stations. Similarly Namche temperature changes by 0.81- 1.32oC per degree change in temperature at corresponding lower elevation at Lukla except in monsoon season (July, August, and September). However, the inconsistent variation observed between the station with a large altitudinal difference (2940m) at Lukla and Kala Pattar. The temperature at Lukla (2660m) changed by 1.24-1.49oC (R2> 0.56) in summer season (April, May, June) and 0.21 and 0.15 in March and November (with negative R2) per degree change in high altitude station Kala Patthar (5600m asl). Seasonal variations in temperature also indicate the similar rate of change in temperature between the corresponding stations at high/low elevation. Comparatively monsoon season showed the weaker correlation/linkage than in the other seasons. The precipitation showed a varied rate of fluctuation between the stations in all the months and seasons.

These strong linkages and a similar range of fluctuation of climatic parameters in the different elevation indicate the possibilities of their use of lower elevation climatic data to represent climate in the higher elevation sites up to the certain level. Similar variations of temperature particularly between the stations in the high elevation (above 4000m) indicate the necessity of the extension of the meteorological stations in those areas for the meaningful study of the high altitude climate. We found that it is possible to use valley bottom climate records to quantitatively assess those at the high elevation on the southern slope of Mt Everest, although corrections are necessary when absolute values of climatic factors are considered especially in snow cover and snow-free areas. This study will be very useful in understanding the high altitude climate change and impact studies.