Comparing Temperature and Humidity Trends in Two Water-Stressed Mountain Environments with Embedded Sensor Networks

Mountain regions are sensitive to climate change, although these sensitivities vary by region. Intercomparing climate trends between mountain ranges thus provides insight into regional and large-scale patterns of climate variability. This investigation compares thirteen years of hourly data from two embedded networks of air temperature and humidity sensors at two sites within the American Cordillera: the tropical Llanganuco valley of the Cordillera Blanca, Peru (10 S); and the midlatitude Great Basin National Park (GBNP), NV, USA (40 N).

This study assesses trends in temperature and humidity, near surface lapse rates, and elevation dependency between 2007 and 2020. The overall daily mean temperature in both locations increased by about 0.50°C over the study period. Daily mean absolute humidity also increased at both locations, but increased 10x faster in Llanganuco than the GBNP. Our results also provide measured evidence of elevation dependent trends. Absolute humidity increased faster at higher elevations than lower elevations at the Peru site, but elevation dependent temperature trends varied by season. Seasonal variation occurred for all elevation dependent assessments in the GBNP. No trends in the near surface monthly mean temperature lapse rates were evident at the GBNP site, whereas lapse rates decreased at a rate of -0.125°C/km per year in Llanganuco. Our results depict significant differences in elevation dependent climate trends at sites separated by 50 degrees of latitude along the longest continuous mountain range on Earth informing improved parameterizations and physical forcing in regional climate models.