Model Evaluation and Intercomparison
The TF HTAP is conducting a series of model evaluation and intercomparison experiments to:- Produce some estimates of intercontinental source-receptor relationships
- Improve our understanding of the variability and uncertainty in current model estimates
- Guide future model developments to decrease uncertainties in source-receptor relationships
The organization of the model evaluation and intercomparison activities was discussed at the TF HTAP workshop in Washington, DC, USA, January 2006, building on the discussion paper "The use of a multi-model approach in support of the UN-ECE LRTAP Task Force on Hemispheric Transport of Pollution." Taking into account the comments and suggestions made by the workshop participants and the need for specific deliverables in 2007 and 2009, the workshop in Washington recommended a series of four sets of experiments:
Set 1. Source-Receptor Emission Sensitivity Studies: The simulations consist of a reference simulation (2001) and simulations reducing anthropogenic emissions by 20% in Europe, North America, East Asia, and South Asia.
Set 2. Process and Tracer Studies: These experiments will develop a simple set of diagnostics that can be used to understand the model differences that occurred under experiment 1. The studies will try to isolate the relative roles of mixing/transport and chemical processes using analyses of CO, colored tracers, Rn222, and NMVOC
Set 3. Detailed Process Studies: These experiments will explore specific process relevant for intercontinental transport. Potential topics include pulsed NOx versus tagging of NOx, mercury fate, aerosols (in conjunction with AEROCOM), comparison of model results to campaigns (TRACE-P and ICARTT), the role climate change and variability, and vertical mixing of ozone.
Set 4. Improved Estimates of Source Receptor Relationships: Building on the previous sets of experiments, this set would generate improved estimates for inclusion in the 2009 assessment report.
The initial experiments, to be started in 2006, will provide estimates of source-receptor relationships and diagnostics of immediate relevance for the 2007 interim report. In the course of 2007 and 2008, depending on the outcome of the first experiments, and on the interest of participants, the experiments can be gradually expanded upon.
The model intercomparison Task Leaders that have volunteered to date are:
| Task | Task Leader | |
| Experiment Set 1: Photooxidants | Frank Dentener |
|
| Arlene Fiore | arlene.fiore@noaa.gov | |
| Experiment Set 1: Aerosols | Michael Schulz | michael.schulz@cea.fr |
| Experiment Set 1: Mercury | Nicola Pirrone | n.pirrone@cs.iia.cnr.it |
| Experiment Set 1: POPs | Sergey Dutchak | sergey.dutchak@msceast.org |
| Experiment Set 2 |
A tentative timeline for the model intercomparison and evaluation experiments is provided below.
