The aerosol model implementation in the Brazilian terrestrial system model (BESM) and its validation with satellite data

Abstract

Scientific Basis and Work Plan The primary objective of the work is to implement the Hamburg aerosol model (HAM) developed at the Max Planck Insti-tute (MPI), Germany into the Brazilian Earth System Model (BESM) as part of the Earth System Model Development project. This new model will be helpful in quantification of aerosol induced changes to future climate. HAM predicts the evo-lution of an ensemble aerosol population as well as their size distribution and composition. This includes the space-time evolution of the following natural and anthropogenic aerosol species: dust, black carbon, sulfate, seasalt and particulate organic matter.The processes pertaining to aerosols include: dry- and wet-deposition, sedimenta-tion, nucleation, coagulation, condensation and thermodynamics. The advanced treatment of aerosols in HAM forms a strong basis for its implementation in BESM. The main challenge of the work is that the aerosol modules related to HAM are not standalone but hardwired into the parent climate model (ECHAM) following the grid and processor architecture of the parent climate model. The communication of aerosol calculations from HAM into its parent model is through a complex, but modularized interface which acts as a single entry point for all aerosol related calculations like initialization, tracer and stream definition, and also allows aerosol processes interacting with the physical climate model at different stages of model integration. The work would focus on designing the necessary compatible interface for BESM and the plan of work in mentioned below1.Understanding the architecture and compatibility of BESM and HAM model2.Development of the BESM-HAM pre-run setup3.Identification of the dependencies of HAM modules on its parent model so as to have a similar mapping with the BESM environment 4.Initiatialisation of the HAM submodel in BESM and inclusion of tracer and stream definitions.5.Develop routines for reading & distributing the HAM inputs into the BESM parallel environment 6.Model Integration phase - physics & dynamic calculations: (1)Identification of the necessary input variables from BESM required for HAM computations and resolve the dependencies (2)Design a scheme for organizing the input variables from BESM into a format compatible to HAM and vice-versa (3) Implementation of aerosol related radiation and microphysical processes into BESM (4)Validation, of the stability and correctness of proceses included at each step(5)conduct simulations with the enhanced BESM model turning on and o the aerosol (HAM) component and compare with reference runs carried out in the initialization phase (6)develop/ adopt routines to handle the restarts and outputs of HAM inside BESM 7.global aerosol model validation (AU)