We improve the canopy module of a very detailed snow model, SNOWPACK, with a view of a more consistent representation of the sub-canopy energy balance with regard to the snowpack. We show that adding a formulation of (i) the canopy heat capacity and (ii) a lowermost canopy layer (alike trunk + solar shaded leaves) yields significant improvement in the representation of sub-canopy incoming long-wave radiations, especially at nighttime. This energy is an important contributor to snowmelt.

The Yale Interactive terrestrial Biosphere model (YIBs) predicts land carbon fluxes and tree growth based on mature schemes but with special updates in phenology, ozone vegetation damage, and photosynthetic-dependent biogenic volatile organic compounds. Evaluations with data from 145 flux tower sites and multiple satellite products show that the model predicts reasonable magnitude, seasonality, and spatial distribution of land carbon fluxes.

Carbon isotopes have been added to the ocean model of the Community Earth System Model version 1 (CESM1). This paper describes the details of how the abiotic 14C tracer and the biotic 13C and 14C tracers were added to the existing ocean model of the CESM. In addition, it shows the first results of the new model features compared to observational data for the 1990s.

In this paper a new mathematical model of volcanic plume, named Plume-MoM, is presented. The model is based on the method of moments and it is able to describe the continuous variability in the grain size distribution (GSD) of the pyroclastic mixture ejected at the vent, crucial to characterize the source conditions of ash dispersal models. Results show that the GSD at the top of the plume is similar to that at the base and that plume height is weakly affected by the parameters of the GSD.

The paper gives a detailed description of the PArallelized Large-eddy simulation Model (PALM) version 4.0 for the simulation of turbulent atmospheric and oceanic boundary layer flows. The model is optimized for use on massively parallel computer architectures and has been applied for various boundary-layer research studies over the last 15 years by various work groups all over the world. Besides the model description, we outline past PALM applications and also discuss future perspectives.

Multi-generational oxidation of organic vapors can significantly alter the mass, chemical composition and properties of secondary organic aerosol (SOA). Here, we implement a semi-explicit, constrained multi-generational oxidation model of Cappa and Wilson (2012) in a 3-D air quality model. When compared with results from a current-generation SOA model, we predict similar mass concentrations of SOA but a different chemical composition. O:C ratios of SOA are in line with those measured globally.

A new approach for modeling photolysis rates (J values) in atmospheres with fractional cloud cover has been developed and is implemented as Cloud-J – a multi-scattering eight-stream radiative transfer model for solar radiation based on Fast-J. Using observations of the vertical correlation of cloud layers, Cloud-J provides a practical and accurate method for modeling atmospheric chemistry, which can be extended to solar heating rates.

Despite its importance, land surface models poorly simulate fire disturbance and its dynamic effects. Here we present a novel and model-independent methodology of implementing a realistic fire size distribution in a dynamic vegetation model by assimilating satellite data and employing blob detection. While focusing on the Arctic, we verify our results against field data and showcase the improved fire representation in the model.

The measurement of snow properties on global scale relies on microwave remote sensing data. The interpretation of the data is however challenging. Here we introduce MEMLS3&a, an extension of the snow emission model MEMLS, to include a backscatter model for active microwave remote sensing. In MEMLS3&a, snow input parameters can be derived by objective measurement methods, which avoids fitting the scattering efficiency of snow. The model is validated with combined active and passive measurements.

Limited area models (LAMs) require lateral boundary conditions that are usually available with an interval of several hours. Consequently, LAMs can miss a rapidly moving item that enters the LAM domain. Here we present how to detect a rapidly moving pressure disturbance in fields provided in the coupling files.

PolarVPRM uses a diagnostic, remote-sensing-based approach optimized for polar regions to estimate net ecosystem CO2 exchange (NEE) between the high-latitude land surface and the atmosphere. PolarVPRM NEE shows close agreement with NEE observed from eddy covariance sites, relative to other models. Examination of per-pixel trends in PolarVPRM NEE and its drivers (North America north of 55 N, 2001-2012) indicate arctic greening and boreal browning in response to changing environmental conditions.

The interparcel mixing algorithm in the Lagrangian advection scheme with shape matrix (LASM) is updated to make the scheme more robust. The new algorithm is more effective in controlling the shape of parcels, which is vital for long time simulation. LASM is inherently shape-preserving without any complicated filter or limiter, so it is linear. This fact contributes to the ability of LASM to preserve the sum of multiple tracers exactly.

Ecosystem-based marine management requires coupling/integrating multiple models in one unified scheme. The widely adopted Ecopath with Ecosim (EwE) is potentially a crucial high trophic level component of such schemes. However, being written in Visual Basic, integration of EwE with physical and/or biogeochemical oceanographic models, which were mostly written in Fortran, is complicated. We release a re-coding of EwE in Fortran (EwE-F) so as to facilitate its coupling/integration in such schemes.