Theoretical and experimental evidences of medium range atmospheric transport processes of polycyclic musk fragrances

Abstract. The radioactive species radon (222Rn) has long been used as a test tracer for the numerical simulation of large scale transport processes. In this study, radon transport experiments are carried out using an atmospheric GCM with a finite-difference dynamical core, the van Leer type FFSL advection algorithm, and two state-of-the-art cumulus convection parameterization schemes. Measurements of surface concentration and vertical distribution of radon collected from the literature are used as references in model evaluation. The simulated radon concentrations using both convection schemes turn out to be consistent with earlier studies with many other models. Comparison with measurements indicates that at the locations where significant seasonal variations are observed in reality, the model can reproduce both the monthly mean surface radon concentration and the annual cycle quite well. At those sites where the seasonal variation is not large, the model is able to give a correct magnitude of the annual mean. In East Asia, where radon simulations are rarely reported in the literature, detailed analysis shows that our results compare reasonably well with the observations. The most evident changes caused by the use of a different convection scheme are found in the vertical distribution of the tracer. The scheme associated with weaker upward transport gives higher radon concentration up to about 6 km above the surface, and lower values in higher altitudes. In the lower part of the atmosphere results from this scheme does not agree as well with the measurements as the other scheme. Differences from 6 km to the model top are even larger, although we are not yet able to tell which simulation is better due to the lack of observations at such high altitudes.

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Transport of short-lived halocarbons to the stratosphere over the Pacific Ocean

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-1163-2020 ◽

2020 ◽

Vol 20 (2) ◽

pp. 1163-1181

Author(s):

Michal T. Filus ◽

Elliot L. Atlas ◽

Maria A. Navarro ◽

Elena Meneguz ◽

David Thomson ◽

...

Keyword(s):

Boundary Layer ◽

Lower Stratosphere ◽

Atmospheric Transport ◽

Convective Transport ◽

Transport Processes ◽

Lagrangian Model ◽

Convection Scheme ◽

Model Calculations ◽

Upper Troposphere ◽

Tropical Troposphere

Abstract. The effectiveness of transport of short-lived halocarbons to the upper troposphere and lower stratosphere remains an important uncertainty in quantifying the supply of ozone-depleting substances to the stratosphere. In early 2014, a major field campaign in Guam in the western Pacific, involving UK and US research aircraft, sampled the tropical troposphere and lower stratosphere. The resulting measurements of CH3I, CHBr3 and CH2Br2 are compared here with calculations from a Lagrangian model. This methodology benefits from an updated convection scheme that improves simulation of the effect of deep convective motions on particle distribution within the tropical troposphere. We find that the observed CH3I, CHBr3 and CH2Br2 mixing ratios in the tropical tropopause layer (TTL) are consistent with those in the boundary layer when the new convection scheme is used to account for convective transport. More specifically, comparisons between modelled estimates and observations of short-lived CH3I indicate that the updated convection scheme is realistic up to the lower TTL but is less good at reproducing the small number of extreme convective events in the upper TTL. This study consolidates our understanding of the transport of short-lived halocarbons to the upper troposphere and lower stratosphere by using improved model calculations to confirm consistency between observations in the boundary layer, observations in the TTL and atmospheric transport processes. Our results support recent estimates of the contribution of short-lived bromocarbons to the stratospheric bromine budget.

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Non-volant modes of migration in terrestrial arthropods

Animal Migration ◽

10.2478/ami-2014-0002 ◽

2014 ◽

Vol 2 (1) ◽

Cited By ~ 7

Author(s):

Don R. Reynolds ◽

Andrew M. Reynolds ◽

Jason W. Chapman

Keyword(s):

Atmospheric Transport ◽

Transport Processes ◽

Biological Processes ◽

Factors Affecting ◽

Terrestrial Arthropods ◽

Taxonomic Range ◽

Migratory Movements ◽

Dispersal Kernels ◽

Typical Mode ◽

Behavioural Adaptations

AbstractAnimal migration is often defined in terms appropriate only to the ‘to-and-fro’ movements of large, charismatic (and often vertebrate) species. However, like other important biological processes, the definition should apply over as broad a taxonomic range as possible in order to be intellectually satisfying. Here we illustrate the process of migration in insects and other terrestrial arthropods (e.g. arachnids, myriapods, and non-insect hexapods) but provide a different perspective by excluding the ‘typical’ mode of migration in insects, i.e. flapping flight. Instead, we review non-volant migratory movements, including: aerial migration by wingless species, pedestrian and waterborne migration, and phoresy. This reveals some fascinating and sometimes bizarre morphological and behavioural adaptations to facilitate movement. We also outline some innovative modelling approaches exploring the interactions between atmospheric transport processes and biological factors affecting the ‘dispersal kernels’ of wingless arthropods

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