British Exploring Society: 2014 expedition to Ladakh in the Indian Himalayas

Abstract

The British Exploring Society has been engaging young people and encouraging them to explore the world for themselves and for future generations, using science as a vehicle to discover and understand the most untouched wildernesses across the globe. Over a 5-week period between late July and late August a group of young explorers aged between 16 and 21 years old were selected to investigate a series of meteorology projects in a high-altitude desert located in Ladakh within the Indian Himalayas. Localised, endemic vegetation belts in high-altitude areas can change with altitude in much the same way that vegetation changes with latitude (Beniston, 2003). They represent unique environmental niches catering for biodiversity ‘hotspots’ (Diaz et al., 2003). However, high-altitude environments can be extremely sensitive to changes in climate (Beniston, 2003; Diaz et al., 2003). They also play an important role in governing the weather and climate both regionally and globally. Moreover, the hydrology of the Ladakh region is changing due to increased melt water from the retreating (Thayyen and Gergan, 2010) and destabilising (Schmidt and Nüsser, 2012) glaciers. Eight of our explorers focused on carrying out a study of the weather of the region and the likely impacts of change, building on the work done by explorers in the previous year. A limited number of weather stations have been installed in the area and discrepancies in weather event frequency (Nandargi and Dhar, 2011) coupled with the extreme flash flooding in 2010 highlighted the necessity of more consistent and long-term weather records. The 2010 catastrophe, which caused large-scale devastation and the loss of 255 lives, was used as a case study for our young explorers in 2013 when they installed the third-highest weather station (at 5300m amsl) along a tributary valley adjacent to the Zara River. The aim was to collect data recorded by the station over the course of a 2-year period. In 2014 our intrepid group of explorers visited the same high reaches of the Indian Himalayas with three objectives in mind. Firstly, to geologically map the area, secondly, to measure ablation rates on the local glaciers and, lastly, to further ongoing meteorological studies conducted in the area by retrieving data recorded in the year that had elapsed. They journeyed to an altitude of 4800m along the Zara Valley over the Tanglang La Pass in Ladakh. To increase their own understanding, the expedition group initially proceeded with a small and dynamic microclimate-monitoring project centred on investigating the orographic effects on weather systems. Over their field study period they took the opportunity to increase their understanding of their local environment and the local adiabatic effects of air rising and falling over the mountains. Thanks to the equipment loaned to us by the Royal Meteorological Society (RMetS), our explorers set up a static weather station at base camp (4875m) using Kestrel 4000 portable weather stations and separate rain gauges. Some of the results obtained from a 6-day study have been outlined below, displaying temperature data contrasted with the recorded relative humidity values. Predictably, we saw a decrease in humidity relative to temperature increase. This is due to an increased capacity in warm air to hold more water vapour prior to saturation point, decreasing the relative humidity. The results are shown in Figure 1. Whilst away from camp explorers made short-term observations using the Kestrel 4500 model to record and store data over the course of a day. The group divided into down-valley and up-valley teams, ensuring there was an altitudinal difference in their two-step monitoring. This was repeated over the course of the expedition to provide a wealth of data with which the group could test their hypotheses. Continued monitoring through the expedition produced temperature data featured in the graph on 18 August 2014, which showed the temperature difference between 5410 and 5700m. The recorded values were higher throughout the day at a lower altitude, exempting 1130 and 1300; in fact at 1430 there was an approximate ~6 degC difference in temperature values. Similar results were recreated on 20 August at the same location, with a high of 32.4°C recorded at the lower altitude site compared with 26.1°C at 5700m. The most notable differences observed between 2013 and 2014 have been the marked contrast in temperature and, in particular, rainfall over the same field study period. Due to the rain shadow cast by the high Himalayan ranges, the monsoonal rains cannot track across to Ladakh and the Kashmir Valley. Typically, total precipitation in August has equated to 18mm (Thsangspa and Raina, 2011) and existing records are indicative that annual rainfall totals are ~250mm in Zanskar, which progressively decreases towards the Indus Valley at ~100mm (Raj and Sharma, 2013). Yet, as per the British Exploring Science Report (2013) ~2–3mm was recorded daily, surpassing original estimates. In contrast to the previous year, conditions in August 2014 could be described as arid; potential temperatures recorded highs of 30°C compared to a high of 18°C in 2013 (Figure 2). Observed precipitation levels were all recorded at 0mm with a few exceptions; there were three occasions when snowfall and hail fell to a depth of 1–2mm along the high reaches of the Zara Valley. In addition to their physical data collection, explorers made sure to record observational changes in weather over the course of their stay and familiarise themselves with local weather patterns. Orographic enhancement of precipitation was logged on several days using the RMetS cloud observation key to note the development of cumulus over the ranges and the subsequent rain shadow on the lee side of the mountain. It was a useful tool in identifying convective processes at work; exemplifying low- and high-level cloud type at different altitudes became part of a daily routine to ensure the explorers were confident in their meteorological observations. An infrared thermometer provided to them allowed the group to assess the temperature difference between cloud types and hone in on their data recording techniques. Anemometers also helped our explorers to identify katabatic drainage and Chinook winds, which were commonly identified wind regimes in the valleys where the field study was set. Results obtained from the weather station which had been in situ for 2 years are currently being analysed and plotted; preliminary investigation of the data has demonstrated that it could act as a promising resource, and the British Exploring Society and its partners look forward to reviewing the published results. Unfortunately, some of the wires linked to the temperature probe sustained damage caused by local wildlife. However, at least 5 months of temperature data was recorded prior to this incident; the station continues to log data on humidity, pressure, wind speed and direction. For full details of the British Exploring Science Report and their results, please get in touch or visit our website!