Observed snow depth trends in the European Alps: 1971 to 2019 The Cryosphere DOI 10.5194/tc-15-1343-2021 9 April 2021 Here, we present an Alpine-wide analysis of snow depth from six Alpine countries – Austria, France, Germany, Italy, Slovenia, and Switzerland – including altogether more than 2000 stations of which more than 800 were used for the trend assessment. Linear trends of monthly mean snow depth between1971 and 2019 showed decreases in snow depth for most stations from November to May. Read more
The enigma of relict large sorted stone stripes in the tropical Ethiopian Highlands Earth Surface Dynamics DOI 10.5194/esurf-9-145-2021 7 April 2021 Large forms of sorted patterned ground belong to the most prominent geomorphic features of periglacial and permafrost environments of the mid-latitudes and polar regions, but they were hitherto unknown in the tropics. Here, we report on relict large sorted stone stripes (up to 1000 m long, 15 m wide, and 2 m deep) on the ca. 4000 m high central Sanetti Plateau of the tropical Bale Mountains in the southern Ethiopian Highlands. Read more
geoChronR – an R package to model, analyze, and visualize age-uncertain data Geochronology DOI 10.5194/gchron-3-149-2021 5 April 2021 Chronological uncertainty is a hallmark of the paleoenvironmental sciences and geosciences. While many tools have been made available to researchers to quantify age uncertainties suitable for various settings and assumptions, disparate tools and output formats often discourage integrative approaches. Here, we describe geoChronR, an open-source R package to facilitate these tasks. Read more
Sensitivities to biological aerosol particle properties and ageing processes: potential implications for aerosol–cloud interactions and optical properties Atmospheric Chemistry and Physics DOI 10.5194/acp-21-3699-2021 2 April 2021 Primary biological aerosol particles (PBAPs), such as bacteria, viruses, fungi, and pollen, represent a small fraction of the total aerosol burden. Given that PBAPs are highly efficient atmospheric ice nuclei (IN) at T > -10 ∘C, we suggest that small changes in their sizes or surface properties due to chemical, physical, or biological processing might translate into large impacts on ice initiation in clouds. Read more
High-resolution optical constants of crystalline ammonium nitrate forinfrared remote sensing of the Asian Tropopause Aerosol Layer Atmospheric Measurement Techniques DOI 10.5194/amt-14-1977-2021 31 March 2021 In this work, we have retrieved the first low-temperature data set of optical constants for crystalline AN in the 800–6000 cm-1 wave number range with a spectral resolution of 0.5 cm-1. We show that our data accurately fit aircraft-borne infrared measurements of ammonium nitrate particles in the upper tropospheric aerosol layer, which is formed during the Asian summer monsoon period. Read more
A statistical–parametric model of tropical cyclones for hazard assessment Natural Hazards and Earth System Sciences DOI 10.5194/nhess-21-893-2021 30 March 2021 We present the formulation of an open-source, statistical–parametric model of tropical cyclones (TCs) for use in hazard and risk assessment applications. We demonstrate the capability of the model to replicate observed behaviour of TCs, including coastal landfall rates which are of significant importance for risk assessments. Read more
A global climatological perspective on the importance of Rossby wavebreaking and intense moisture transport for extreme precipitation events Weather and Climate Dynamics DOI 10.5194/wcd-2-129-2021 29 March 2021 Extreme precipitation events (EPEs) frequently cause flooding with dramatic socioeconomic impacts in many parts of the world.Previous studies considered two synoptic-scale processes, Rossby wave breaking and intense moisture transport, typically in isolation, and their linkage to such EPEs in several regions. This study presents for the first time a global and systematic climatological analysis of these two synoptic-scale processes, in tandem and in isolation, for the occurrence of EPEs. Read more
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard Annales Geophysicae DOI 10.5194/angeo-39-277-2021 26 March 2021 This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). One possible explanation for this is Farley–Buneman instabilities of strong local currents. In the present study, we provide an overview of the observations and discuss their characteristics and potential generation mechanisms. Read more
Model physics and chemistry causing intermodel disagreement within the VolMIP-Tambora Interactive Stratospheric Aerosol ensemble Atmospheric Chemistry and Physics DOI 10.5194/acp-21-3317-2021 25 March 2021 As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), several climate modeling centers performed a coordinated pre-study experiment with interactive stratospheric aerosol models simulating the volcanic aerosol cloud from an eruption resembling the 1815 Mt. Tambora eruption (VolMIP-Tambora ISA ensemble). Read more
Comparison of ozone measurement methods in biomass burning smoke: anevaluation under field and laboratory conditions Atmospheric Measurement Techniques DOI 10.5194/amt-14-1783-2021 24 March 2021 In recent years wildland fires in the United States have had significant impacts on local and regional air quality and negative human health outcomes. Although the primary health concerns from wildland fires come from fine particulate matter (PM2.5), large increases in ozone (O3 have been observed downwind of wildland fire plumes. The chemiluminescence FRM method is highly recommended for accurate measurements of O3 in wildland fire plume studies and at regulatory ambient monitoring sites frequently impacted by wildland firesmoke. Read more