Surface-based temperature inversion characteristics and impact on surface air temperatures in northwestern Canada from radiosonde data between 1990 and 2016

Abstract

Assumptions of linear lapse rates in regions prone to surface-based inversions can generate biases in the prediction of surface air temperature. Although studies of Arctic inversions are common, few regional studies of their characteristics exist in high-latitude regions with mountainous topography. To address this gap, vertical atmospheric temperature profiles for five sites in northwestern Canada were analysed using archived radiosonde data from 1990-2016. We present monthly, seasonal, and annual SBI characteristics including the occurrence of transient and persistent SBIs. A novel metric, surface-based inversion impact (SBI<sub>imp</sub>), was developed by combining the traditional inversion characteristics of depth, strength, and frequency, and was used to quantify the impact of surface-based inversions on cooling the surface-air temperature. SBI<sub>imp</sub> values of > 5°C yr<sup>-1</sup> and ~ 10°C winter<sup>-1</sup> occur locally. A weak linear relationship between sea ice coverage in the Beaufort Sea and SBIimp manifests across parts of the study area, though this relationship does not persist after detrending the datasets. Topographic analysis of areas surrounding each radiosonde location reveal highly variable SBI<sub>imp</sub> in complex mountain areas and more consistent SBI<sub>imp</sub> across areas of low relief. Our results can help interpret the role of inversions in climatic conditions maintaining cryospheric elements such as permafrost.

Factors limiting the potential range expansion of lodgepole pine in Interior Alaska

“…The final environmental covariates tested in our models were: (1) residual SOL depth, because of its direct relationship with seedling germination and initial survival, mediated through controls over soil temperature and availability of moisture and nutrients (Greene et al, 2007; Johnstone & Chapin, 2006); (2) site moisture class, as gradients in soil drainage and moisture availability structure plant communities and natural seedling recruitment in the study area (Johnstone et al, 2010); (3) soil pH, as an indicator of soil chemistry variations that affect nutrient availability and plant communities (Hollingsworth et al, 2006); and (4) summer (June to August) mean temperature, which represents variations in climate severity occurring with elevation and latitude across our study sites. Summer temperature was selected over annual temperature because it captures growing season conditions and winter temperature is known to have complicated interactions with topographic inversions (Noad et al, 2023). We also recognize that there are linkages between site moisture class and SOL depth, but each provides some unique information due to variations in fire history, severity, and permafrost (Johnstone et al, 2020).…”

What Is the Threshold Elevation at Which Climatic Factors Determine Snow Cover Variability? A Case Study of the Keriya River Basin

“…The impact of climate on snow cover exhibits elevation-dependent changes, which may be attributed to variations in climatic factors. Affected by the lapse rate, air temperature gradually decreases as elevation increases, which is further complicated by temperature inversion phenomena within mountainous areas [20][21][22][23]. Notably, prior investigations have elucidated evident vertical gradients in precipitation alterations, with a conspicuous maximum precipitation zone [24,25].…”