The CLaMS sedimentation module sedi
The program sedi
The program sedi calculates the trajectories of individual NAT-particles. Horizontal motion is given from the wind fields whereas vertical motion (sedimantation) is calculeted from the settling velocity of the particles. Dynamical uptake and release of HNO3 from/into the gas phase are calulated. For that the output for the nearest neighbors of the chemistry simulation is interpolated to the particle trajectory locations. The HNO3 field in the chemisty output file are then adjusted according to Denitrification and Renitrification.
Input files
sedi needs two input files with the information of the particles. The first sedi.nc is the last days' output and contains position and parameters of the NAT accumulated surviving particles the second file add_sedi.nc contains the new built NAT particles added through nucleation.
To run the model, one further needs the file bgr_sedi.nc that contains hourly HNO3 and H2O output for the chem simulation.
The file sedi.inp controls the run of sedi and includes all necessary files.
The program pos_sedi
The programm pos_sedi creates a set of newly nucleated particles equally distributed over the area where T < T_NAT.
Levels and resolution are comparable to the program pos_area
It is advised to use this for particle nucleation as the positions should be independent of the positions of the CLaMS air parcels.
An effective nucleation rate must be calculated from the ratio of particle parcels per air parcel.
Examples for Resolution/Aspect Ratio (Grooß et al., 2005, Winter 2002/03):
CLaMS |
Resolution pos_sedi |
NAT desity[m^-3] |
Nucleation Rate |
100km/250 |
66.7km/300 |
47 |
7.8×10−6 cm−3 h−1 |
|
|
20 |
3.3×10−6 cm−3 h−1 |