Quantifying aerosol presence and composition over Earth's ice sheets and glaciers - mapping anthropogenic and natural aerosol patters and estimating changes over time
Many of Earth’s glaciers have been losing mass at an alarming rate in the past few decades. Both anthropogenic and natural aerosols deposited on snow and ice can darken reflective surfaces, increase solar absorption and subsequently enhance snow and ice melt rates. This project seeks to map aerosols over Earth's cryosphere using the global land ice identification mask and monthly mean MERRA-2 aerosol data. Ideally, the project will be completed for all of Earth, mapping aerosol concentrations, with seasonal and annual totals from 1980-present. If time/space limits us, the project can be reduced geographically (e.g. Arctic or Himalaya) and temporally (2000-present).
Randolph Glacier Inventory Data, RGI 5.0, delineates the spatial extent of Earth’s glaciers. Data format = SHP shapefile, vector format. File size: whole inventory 410 mb zipped, 739 MB unzipped, 125 files, organized by 19 regions.
- 01_Alaska
- 02_WesternCanadaUS
- 03_ArcticCanadaNorth
- 04_ArcticCanadaSouth
- 05_GreenlandPeriphery
- 06_Iceland
- 07_Svalbard
- 08_Scandinavia
- 09_RussianArctic
- 10_NorthAsia
- 11_CentralEurope
- 12_CaucasusMiddleEast
- 13_CentralAsia
- 14_SouthAsiaWest
- 15_SouthAsiaEast
- 16_LowLatitudes
- 17_SouthernAndes
- 18_NewZealand
- 19_AntarcticSubantarctic
MERRA-2 Aerosol Raster Modeled Data. Required input data, filename M2TMNXAER.5.12.4, consists of monthly mean dust, organic carbon, black carbon, sea salt and sulfate aerosol surface mass concentration and scattering aerosol optical thickness (AOT).
Scientific data set (SDS) or bands are:
- BCSCATAU - Black Carbon Scattering AOT (550 nm)
- BCSMASS - Black Carbon Surface Mass Concentration
- OCSCATAU - Organic Carbon Scattering AOT (550 nm)
- OCSMASS - Organic Carbon Surface Mass Concentration (Particulate Matter)
- DUSCATAU - Dust Scattering AOT (550 nm)
- DUSMASS - Dust Surface Mass Concentration
- SSSCATAU - Sea Salt Scattering AOT (550 nm)
- SSSMASS - Sea Salt Surface Mass Concentration
- SUSCATAU - SO4 Scattering AOT (550 nm)
- SO4SMASS - SO4 Surface Mass Concentration
- SO2SMASS - SO2 Surface Mass Concentration
- TOTSCATAU - Total Aerosol Scattering AOT (550 nm)
MERRA-2 monthly surface albedo is available from filename M2TMNXRAD.5.12.4, SDS:
- ALBEDO - surface albedo
To get the data, visit DISC data ordering site or Direct download via ftp://goldsmr4.sci.gsfc.nasa.gov/data/s4pa/.
More info can be found in this pdf.
MERRA-2 data has a resolution of 0.625 degrees (longitude) (576 grid points) by 0.5 degrees (latitude) (361 grid points) or approximately 50km spatial resolution. Data format = NetCDF-4. File sizes ~3-155 MB per monthly mean file.
CALIOP aerosol raster observation Version 3, Level 3 Aerosol Profile, Cloud Free data Monthly global gridded data, nighttime aerosol extinction profiles, cloud-free. Filename is "CAL_LID_L3_APro_CloudFree_Standard-V3-00.hdf" Available from 2006-present, between latitudes of 85 degrees North to 85 degrees South. Sun synchronous orbit, equator crossing time of 2 pm, 16-day orbit repeat cycle. Spatial resolution 2 degrees in latitude, 5 degrees in longitude. Observations are to be compared with modeled MERRA-2 aerosol results. To get data, visit ASDC HTML Order Tool / CALIPSO Data Products Catalog / CALIPSO Data User's Guide Data format = HDF. File size ~180 MB.
Scientific data set (SDS) or bands are:
- Longitude_Midpoint
- Latitude_Midpoint
- AOD_Mean_Dust
- AOD_Mean_Smoke
- AOD_Mean_Polluted_Dust
- AOD_Mean
MODIS, Aqua, Collection 6, 8-day surface reflectance raster data, to be collected coinciding with season or year corresponding to aerosol data. To learn more and access data: [LPDAAC website data ordering]
(https://lpdaac.usgs.gov/dataset_discovery/modis/modis_products_table/myd09a1)
or Online list of data
Data format = HDF.
File size ~20-80 MB per tile. 460 tiles to cover Earth (see MODIS Grid),MODIS Metadata tiles are 10 degrees by 10 degrees at the equator.
Scientific data set (SDS) or bands are:
- Surface reflectance for band 1
- Surface reflectance for band 2
- Surface reflectance for band 3
- Surface reflectance for band 4
- Surface reflectance for band 5
- Surface reflectance for band 6
- Surface reflectance for band 7
- Surface reflectance 500m quality control flags
- Solar zenith
- View zenith
- Relative azimuth
- Surface reflectance 500m state flags
- Surface reflectance day of year
Landsat Data to be used for smaller mountain, peninsula, coastal glaciers. Reflectance data will be collected to coincide with measured aerosol season or year (e.g. spring or annual). Landsat, raster, surface reflectance data To learn more and access data: Landsat website File size ~2.5 GB per Landsat scene, all 7 spectral bands, 190 km x 180 km area per file. Data format = GeoTIFF. Landsat 4-7 Surface Reflectance User Guide (data from 1982-present) Landsat 8 Surface Reflectance User Guide (data from 2013-present) Landsat sensor versions/history GitHub tool for bulk downloading Landsat orders
Scientific data set (SDS) or bands are: (Note Landsat filenames use the sensor id (LXX), path (PPP), row (RRR), year (YYYY), julian date (DDD), followed by 'sr') (Sensors LE7 for Landsat 7 Enhanced Thematic Mapper, LT5 for Landsat 5 Thematic Mapper, LT4 for Landsat 4 Thematic Mapper). GeoTIFF files have latitude/longitude information in file format.
- Surface reflectance for band 1
- Surface reflectance for band 2
- Surface reflectance for band 3
- Surface reflectance for band 4
- Surface reflectance for band 5
- Surface reflectance for band 6
- Surface reflectance for band 7
- Surface reflectance atmospheric opacity
- Surface reflectance adjacent cloud QA
- Surface reflectance cloud QA
- Surface reflectance cloud shadow QA
- Surface reflectance snow QA
- Cloud mask band (CF mask)
- CF mask confidence band
Python (matlab, idl, ENVI/IDL, ArcGIS - commonly used proprietary software)
Daac2Disk tool or LP DAAC data pool / ftp or http download - for downloading MODIS data
pyMODIS -- mosaicing/reprojecting/gridding/downloading MODIS data
MODIS Grid -- information on MODIS grid / tiles
hdfgroup.org website -- information / tools /readers for understanding MODIS, CALIOP HDF formats
Randolph Glacier Inventory 5.0
CALIOP Website, Tools, Information