An hourly ground temperature dataset for 16 high-elevation sites (3493–4377 m a.s.l.) in the Bale Mountains, Ethiopia (2017–2020)

Alexander R Groos,Janik Niederhauser,Falk Hänsel,Wolfgang Zech,Luise Wraase,Bruk Lemma,Naki Akçar,Mekbib Fekadu,Heinz Veit

doi:10.5194/essd-14-1043-2022

Abstract

Abstract. Tropical mountains and highlands in Africa are under pressure because of anthropogenic climate and land-use change. To determine the impacts on the afro-alpine environment and to assess the potential socio-economic consequences, the monitoring of essential climate and environmental variables at high elevation is fundamental. However, long-term temperature observations on the African continent above 3000 m are very rare. Here we present a consistent multiannual dataset of hourly ground temperatures for the Bale Mountains in the southern Ethiopian Highlands, which comprise Africa's largest tropical alpine area. The dataset covers the period from January 2017 to January 2020. To characterise and continuously monitor the mountain climate and ecosystem of the Bale Mountains along an elevation gradient from 3493 to 4377 m, ground temperature data loggers have been installed at seven sites at 2 cm depth; at four sites at 10 cm depth; and at five sites at 2, 10, and 50 cm depth. The statistical analysis of the generated time series reveals that ground temperatures in the Bale Mountains are subject to large daily fluctuations of up to 40 ∘C and minor seasonal variations on the order of 5 to 10 ∘C. Besides incoming short-wave radiation, ground moisture, and clouds at night, slope orientation and the type of vegetation coverage seem to be the main factors controlling daily and seasonal ground temperature variations. On the central Sanetti Plateau above 3800–4000 m, the mean annual ground temperature ranges from 9 to 11 ∘C. However, nocturnal ground frost down to a depth of 5 cm occurs frequently during the dry season from November to February. At the five sites where ground temperature is measured at three depths, the monitoring will be continued to trace long-term changes. To promote the further use of the ground temperature dataset by the wider research community dealing with the climate and geo-ecology of tropical mountains in eastern Africa, it is made freely available via the open-access repository Zenodo: https://doi.org/10.5281/zenodo.6047457 (Groos et al., 2022).

Highlights

Tropical mountains and highlands cover only a relatively small area of the terrestrial surface, but they comprise a variety of landscapes, ecosystems, and climates and provide essential ecosystem services (e.g. Buytaert et al, 2011; Peters et al, 2019)
Many of the installed data loggers were collected in January 2020 after 3 years of operation, but the hourly ground temperature monitoring will be continued at five sites between 3877 and 4377 m on the Sanetti Plateau and on Mount Wasama to study the long-term climate and environmental change at high elevation
Tropical mountains and highlands in Africa are under pressure because of anthropogenic climate and landuse change, long-term monitoring programmes of essential climate and environmental variables are lacking in most afro-alpine areas

Summary

Introduction

Tropical mountains and highlands cover only a relatively small area of the terrestrial surface, but they comprise a variety of landscapes, ecosystems, and climates and provide essential ecosystem services (e.g. Buytaert et al, 2011; Peters et al, 2019). The local impacts of ongoing anthropogenic climate and land-use change on individual tropical mountains are difficult to assess, but general developments such as the continuous shrinkage of mountain glaciers, the elevational shift in ecosystem boundaries, and the loss of certain habitats and species are evident (e.g. Kaser, 1999; Colwell et al, 2008; Buytaert et al, 2011; Peters et al, 2019; Rahbek et al, 2019; Veettil and Kamp, 2019). Other effects such as the reduction in the organic carbon storage potential below ground, associated with drier and warmer soil conditions, are discussed as well in this context (Buytaert et al, 2011). The tropical highlands and mountains in eastern Africa are either underrepresented or neglected in large-scale climate studies on high-elevation warming (e.g. Diaz and Bradley, 1997; Pepin and Seidel, 2005; Rangwala and Miller, 2012)

Results

Discussion

Conclusion