AWE Visualization

The AWE data is described following the swath in terms of x_along_track and y_cross_track. Each x,y has an associated lat-lon coordinate and the entire dataset is padded with NaN values. To translate this data from NetCDF, a python reader is supplied in the CGCAM repository: convert_assim_data.py. To learn more about the python reader and installing dependencies see Data Assimilation Facility

Data Translation

Current options allow writing the center of the path and visualizing in Paraview. The data is processed in the writeAWE routine where the data is cleaned and flattened before written in vtk format as a cluster of points.

An example input file input_convert.py:

import datetime

# Define source
source='awe'

# Date file extension
ext='2024023T0928_00967'

# Translate extention to year and month for data path
year = int(ext[0:4])
doy  = int(ext[4:7])
date = datetime.datetime(year, 1, 1) + datetime.timedelta(days=doy-1)
month = f"{date.month:02d}"

NAME = [source+ext]
SOURCE = [source]
FILE_NAME = ['awe_l3c_q20_%s_v01.nc' %ext]
PATH = ['/awedata/soc/l3c/%s/%s/' %(year, month)]

VARIABLES=['Radiance']

# Write path along track with percent visibility
write_path = True
path_visibility = 0.05

# Write vtk - Bounds use midpoint of scan
write_vtk = True
lat0 = 30
lat1 = 40
lon0 = -120
lon1 = -90

Search Algorithm

A binary database is generated from make_awe_database using a linear approximation of the center of each swath (output of write_path). An 18 character unique extension is followed by n_points in latitude-longitude space for each scan. The search_awe algorithm then determines if the distance from a given location to each linear segment is within tolerance. It should be noted that these computations are preformed in latitude-longitude space with distance expressed in degrees. The number of line segments used for the linear approximation is a parameter set in both programs and is the identifier in the naming convention of the database awe_database_seg*.dat. A database directory is available on the AWE system /dataST/adam/assim/data/awe/path_database (Note: This directory is pointed to in search_awe)

search_awe [-lat latitude] [-lon longitude] [-dist distance_tolerance]