GASS Projects are listed below with descriptions and contact information for anyone interested in learning more about a particular project.
Impact of Initialized Land Temperature and Snowpack on Sub-Seasonal to Seasonal Prediction Phase II (LS4P-II)
Co-Chairs: Yongkang Xue, Aaron Boone, Tandong Yao
After the completion of the LS4P Phase I , which focused on the impact of the Tibetan Plateau land surface temperature/subsurface temperature (LST/SUBT) on the subseasonal to seasonal (S2S) precipitation prediction, the LS4P Phase II will focus on the Rocky Mountain LST/SUBT effect on S2S prediction and the interaction between Tibetan Plateau Index (TPI) and Rocky Mountain Index (RMI).
This project (LS4P-II) intends to address two questions:
More detailed information on participants and participation, timeline, stages, publication, etc., can be found here.
Improving the Simulation of Diurnal and Sub-Diurnal Precipitation over Different Climate Regimes
Contacts: Shaocheng Xie, David Neelin, Peter Bechtold, Hsi-Yen Ma
As understanding and improving the modeling of diurnal and sub-diurnal precipitation processes can have a broad impact on the fidelity of climate simulations, this proposed GASS project focuses on advancing the model capability through multimodel intercomparison studies against observations.
The overall goals are:
Potential research themes are:
More information on the modeling approach, participation, timelines, coordination with other projects, and publication can be found here.
GEWEX Upper Tropospheric Clouds and Convection Process Evaluation Study (UTCC PROES)
Contact: Claudia Stubenrauch
The GEWEX UTCC PROES working group aims to gain a better understanding of the interconnection between the convection and the properties of the outflowing anvils. The focus will be widened to the role of cirrus originating from in situ freezing driven by large-scale forcing, via a link to the Stratosphere-troposphere Processes And their Role in Climate (SPARC) Project.
More information about this project can be found here
Boundary Layer Cloud Projects
Contact: Adrian Lock
The Boundary Layer Cloud Projects will improve the physical parameterizations of clouds and cloud-related processes and their interactions.
More information about this project can be found here.
Continuous Intercomparison of Radiation Codes (CIRC)
Contacts: Lazaros Oreopoulos, Eli Mlawer
CIRC is intended as an evolving and regularly updated reference source for evaluation against “line-by-line” standards of radiative transfer codes used in Global Climate Models and other atmospheric applications. CIRC differs from previous intercomparisons in that it relies on an observationally validated catalogue of cases. It is currently completing Phase I.
More information about this project can be found here.
Clouds Above the United States and Errors at the Surface (CAUSES)
Contacts: Cyril Morcrette and Hsi-Yen Ma
CAUSES is a joint GASS/DOE-RGCM/DOE-ASR project that aims to use observational data from the Atmospheric Radiation Measurement (ARM) program’s Southern Great Plains (SGP) site to understand the role that clouds have in creating the surface temperature error seen over the American mid-west in a number of general circulation models.
More information about this project can be found here.
CFMIP-GASS Intercomparison of LES and SCMs (CGILS)
Contacts: Minghua Zhang, Chris Bretherton, Peter Blossey
CFMIP Website: https://www.cfmip.org/
The objective of CGILS is to improve understanding and simulation of boundary-layer cloud feedbacks on climate through intercomparison of LES and single-column models forced by idealized climate perturbations.
Cirrus Model Intercomparison Project (CMIP)
Contact: Andreas Muhlbauer
CMIP investigates the microphysical and macrophysical evolution and life cycle of a synoptically-driven cirrus and to compare simulated cirrus cloud properties and radiative effects among models.
Demistify: An LES and NWP Fog Modeling Intercomparison
Contact: Ian Boutle
This GASS project presents an opportunity to form a community and address challenges related to fog modeling. In the first stage of the project, participants are planning a Large Eddy Simulation (LES) and Numerical Weather Prediction (NWP) model intercomparison using data from the Local and Non-local Fog Experiment (LANFEX, Price et al., 2018).
Key questions to be answered include:
More detailed information on participants and participation, timeline, stages, and publications can be found here.
GEWEX Atmospheric Boundary Layer Study 3 (GABLS-3)
Contacts: Bert Holtslag and Gunilla Svensson
GABLS-3 Websites: http://projects.knmi.nl/gabls/index.html
GABLS coordinates research on boundary layer physics to improve the representation of the atmospheric boundary layer in models. The GABLS-3 large-eddy simulation (LES) intercomparison case is based on a moderately stratified, baroclinic, mid-latitude boundary layer observed over Cabauw, the Netherlands on 1 July 2006.
GEWEX Atmospheric Boundary Layer Study 4 (GABLS-4)
Contact: Eric Bazile
This GABLS case study examines the interaction of a boundary layer of strong stability with a surface possessing a low conductivity and a high cooling potential, such as snow. The case is explored using observations at the Antarctic Plateau, and the intercomparison involves land-snow surface models, single column models, and large eddy simulations.
More information about this project can be found here.
Grey Zone Project: Cold Air Outbreak Intercomparison Case
Contact: Pier Siebesma
The goal of the Grey Zone Project is to systematically explore the capability of climate and weather models to represent cloud and convective processes in the resolution range between 1 and 10 km (the so called grey zone) in support of the development of scale adaptive parameterizations for these processes. As a first activity, a comprehensive intercomparison case for a cold air outbreak such as observed during the CONSTRAIN field campaign has been developed.
More information about this project can be found here.
Impact of Initialized Land Temperature and Snowpack on Sub-Seasonal to Seasonal Prediction (LS4P)
Co-Chairs: Yongkang Xue, Tandong Yao, Aaron Boone
The focus area of the first phase of this project will be the Tibetan Plateau, and will be a joint effort with the Third Pole Experiment (TPE) Earth System Model (ESM) inter-comparison project (TPEMIP). This project intends to address two questions:
This project focuses more on the process understanding and predictability rather than operational S2S prediction.
More detailed information on participants and participation, timeline, stages, publication, etc., can be found here.
Microphysics Project
Contact: Ben Shipway
This project aims to create a better understanding of the differences between 3-D models in different intercomparison cases.
More information about this project can be found here.
Polar Cloud Project
Contacts: Mikhail Ovchinnikov, Hugh Morrison
The Polar Cloud Project seeks to understand the role of dynamical and microphysical processes and their interactions in mixed-phase Arctic clouds.
Surface Drag and Momentum Transport
Contacts: Irina Sandu, Louise Nuijens, Annelize van Niekerk
With this project GASS provides the framework for bringing together the observational and modelling communities for efforts to constrain and thereby improve the representation of drag processes such as orographic drag, convection momentum transport etc. More detailed information on this initiative and its timeline can be found here.
A first project in this initiative aims at understanding the impact of resolved and parametrized orographic drag on the atmospheric circulation through the COORDEnation of model experiments and output from several modeling centres. The protocol of the COORDE inter-comparison project follows the study Van Niekerk et al. (2018) and can be found here. COORDE is led by Annelize van Niekerk and Irina Sandu. The idea is to use high and low resolution simulations over some of the most complex mountain chains to identify caveats of blocking and gravity
wave drag parametrizations.
The main focus will be on the Himalayas, and, optionally, other complex orography such as the Caucasus. The main questions are:
More detailed information on participants and participation, timeline, etc., can be found here.
Vertical Structure and Diabatic Processes of the Madden-Julian Oscillation: A joint project with the MJO Task Force using YOTC data
Contacts: Xianan Jiang and Prince Xavier
The objective of this project is to understand the role that convection, cloud, radiative, and dynamic processes play in the development and evolution of the MJO in order to achieve better fidelity of the MJO in global prediction models.
