In MazamaScience/MazamaSatelliteUtils: Utilities for Working with Model and Satellite Data as Rasters

Each GOES satellite hovers over a fixed location on the globe. GOES-16 is positioned at (0°N, 75.2°W) and GOES-17 at (0°N, 137.2°W). The further these satellites scan from their position, the further apart their sample points will be. This means that there will be a high density of readings directly under each satellite and a low density further away.

We can visualize this by drawing a raster of a GOES scan where each cell is colored by the total number of sample points that fall within its bounds:

library(MazamaSatelliteUtils)
library(MazamaSpatialUtils)

setSatelliteDataDir("~/Data/Satellite")
setSpatialDataDir("~/Data/Spatial")

loadSpatialData("NaturalEarthAdm1")

knitr::opts_chunk$set(echo = TRUE)

goesaodc_downloadScanFiles(
  satID = "G16",
  datetime = "2021-05-12 09:00",
  timezone = "America/Chicago"
)

goesaodc_downloadScanFiles(
  satID = "G17",
  datetime = "2021-05-12 09:00",
  timezone = "America/Chicago"
)

scanFileG16 <- goesaodc_listScanFiles(
  satID = "G16",
  datetime = "2021-05-12 09:00",
  timezone = "America/Chicago"
)

scanFileG17 <- goesaodc_listScanFiles(
  satID = "G17",
  datetime = "2021-05-12 09:00",
  timezone = "America/Chicago"
)

scanRasterG16 <- goesaodc_createScanRaster(
  filename = scanFileG16,
  cellSize = 0.1,
  dqfLevel = 3,
  fun = "count"
)

scanRasterG17 <- goesaodc_createScanRaster(
  filename = scanFileG17,
  cellSize = 0.1,
  dqfLevel = 3,
  fun = "count"
)

goesaodc_plotScanRaster(
  raster = scanRasterG16,
  legendLimits = c(0, 25),
  stateCodes = datasets::state.abb,
  legendTitle = "# readings",
  title = "GOES-16 Readings Per .1°x.1° Cell"
)

goesaodc_plotScanRaster(
  raster = scanRasterG17,
  legendLimits = c(0, 25),
  stateCodes = datasets::state.abb,
  legendTitle = "# readings",
  title = "GOES-17 Readings Per .1°x.1° Cell"
)

It's important to keep this distortion in mind when choosing which satellite to use for analyzing a region's AOD data. The GOES-16 satellite has a scan range covering the entire CONUS at DQF levels of 2 or higher, but it has fewer sample points over the west coast states compared to GOES-17.

MazamaScience/MazamaSatelliteUtils documentation built on Dec. 17, 2021, 3:20 a.m.