Elevating Meteorological Understanding on Everest: Installing the Highest Weather Stations on Earth

The highest elevations in the Hindu Kush-Karakorum-Himalayan region are among the most rapidly changing environments on the planet and of immense hydro-climatological significance, yet in-situ meteorological observations are largely non-existent above ~5,500 m. As a result, scientific understanding of glacier-climate interactions, paleoclimatic reconstructions from ice cores, and future high-elevation climate change remains limited. As part of the most comprehensive single research expedition to date in the region, our team installed a network of five automatic weather stations (AWSs) at elevations ranging from 3,810 m to 8,430 m asl during the National Geographic and Rolex Perpetual Planet Extreme Expedition to Mt. Everest in April and May 2019. The Balcony (8,430 m) and South Col (7,945 m) AWSs are the highest ever installed. Each station at the minimum records temperature, relative humidity, barometric pressure, and wind speed/direction; all but the Balcony AWS records incoming and outgoing short and long-wave radiation. Phortse (3,810 m), Pumori Bench (5,315 m), and Camp II (6,464 m) AWSs include snow depth sensors, whereas Phortse and Pumori Bench also feature a full suite of precipitation sensors, including a weighing precipitation gauge enclosed in a double-alter shield and a present weather sensor. Real-time data are transmitted via satellite telemetry to the National Geographic Society’s public website using the Thuraya network. In this presentation we: 1) summarize the methods used in calculating design standards from ERA-Interim reanalysis data for each site; 2) discuss the power management, sensor specifications, and telemetry for each AWS; 3) highlight the numerous challenges specific to installing stations and conducting scientific research above 8,000 m; and 4) share initial insights from the observations during the monsoon, post-monsoon, and early winter periods. The AWS network will greatly improve climber safety on the main climbing routes on the south side of Mt. Everest through real-time meteorological monitoring and bias correction of numerical model output. The highest stations in particular will enable the first in-situ characterization of the climate at the highest points on Earth, and will improve paleoclimatic reconstructions from nearby ice cores.