ICON-HAM-lite: simulating the Earth system with interactive aerosols at kilometer scales
Abstract:
Aerosols strongly influence Earth's climate as they scatter and absorb radiation and serve as condensation nuclei for cloud droplets and ice particles. New Earth system models that run at kilometer resolutions allow us to examine long-standing questions related to these interactions. To perform kilometer-scale simulations with the Earth system model ICON-MPIM, we developed the one-moment aerosol module HAM-lite. HAM-lite was derived from the two-moment module HAM. Like in HAM, aerosols are represented as an ensemble of log-normal modes. Unlike in HAM, aerosol sizes and compositions are prescribed, which reduces the computational costs significantly. Here, we present a first global simulation with four aerosol modes at a resolution of five kilometers and over a period of one year. The simulation captured key aerosol processes including, for example, the emission of dust aerosols by convective storms in the Sahara and the interactions between sea salt aerosols and tropical cyclones in the Pacific.Synoptic Scale Controls and Aerosol Effects on Fog and Low Stratus Life Cycle Processes in the Po Valley, Italy
Abstract:
Fog and low stratus clouds (FLS) form as a result of complex interactions of multiple factors in the atmosphere and at the land surface and impact both the anthropogenic and natural environments. Here, we analyze the role of synoptic conditions and aerosol loading on FLS occurrence and persistence in the Po valley in northern Italy. By applying k鈥恗eans clustering to reanalysis data, we find that FLS formation in the Po valley is either based on radiative processes or moisture advection from the Mediterranean sea. Satellite鈥恇ased data on FLS persistence shows longer persistence of radiatively formed FLS events, likely due to air mass stagnation and a temperature inversion. Ground鈥恇ased aerosol optical depth observations further reveal that FLS event duration is significantly higher under high aerosol loading. The results underline the combined effect of topography, moisture advection and aerosol loading on the FLS life cycle in the Po valley.Multifractal Analysis for Evaluating the Representation of Clouds in Global Kilometre-Scale Models
Multifractal Analysis for Evaluating the Representation of Clouds in Global Kilometer-Scale Models
Abstract:
Association between feel-like temperatures and injury risk during international outdoor athletic championships: a prospective cohort study on 29 579 athlete starts during 10 championships
Abstract:
Objective: To analyse associations between feel-like temperatures measured with the universal thermal climate index (UTCI) and injury rates during international athletic championships.
Methods: During 10 international outdoor athletic championships from 2007 to 2022, in-competition injuries were collected by medical teams and local organising committees. UTCI was extracted hourly from a global reanalysis of observed atmospheric conditions during each championship. We performed Poisson regressions with incidence rates (number of injuries per 1000 athlete starts) as outcomes and UTCI as a predictive variable adjusted for sex, for all and time-loss injuries, for different injured tissue types (ie, muscle, tendon, ligament, articular, bone and skin) and specific discipline (ie, sprints, hurdles, jumps, throws, middle distance, long distance, marathon and race walking).
Results: A total of 1203 in-competition injuries were reported for 29 579 athlete starts. For all in-competition injuries (ie, all injured tissue types and all disciplines), higher UTCI was associated with lower incidence rates for time-loss injuries (IRR=0.98, 95% CI 0.97 to 0.98) but not for all injuries (IRR=1.00, 95% CI 1.00 to 1.01). Based on injured tissue type with all disciplines included, higher UTCI was associated with lower incidence rates for all (IRR=0.97, 95% CI 0.97 to 0.98) and time-loss (IRR=0.96, 95% CI 0.96 to 0.96) muscle injuries. Based on the specific discipline, higher UTCI was associated with lower incidence rates for all and time-loss muscle injuries for sprints (IRR=0.95, 95% CI 0.95 to 0.96, and IRR=0.94, 95% CI 0.93 to 0.94, respectively), hurdles (IRR=0.97, 95% CI 0.96 to 97, and IRR=0.95, 95% CI 0.94 to 0.96, respectively) and throws (IRR=0.97, 95% CI 0.97 to 0.98).
Conclusions: Higher feel-like temperatures were associated with a decreased risk of time-loss and muscle injuries, particularly in sprints, hurdles and throws. Although the precise mechanism for lower injury rates with higher feel-like temperatures requires further investigation, adapting preparations such as warm-up or clothing to forecasted weather conditions may be of benefit.