# Presentation: 531434

## Organization of  MODIS Atmosphere Products

- Rich Kleidman   Science Systems and Applications
- Rob Levy            Science Systems and Applications
- Lorraine Remer  NASA Goddard Space Flight Center
- Shana Mattoo,, Alan Chu, Vanderlei Martins, Rong-Rong Li, and Yoram Kaufman

## MODIS Product Hierarchy

- Level 2 Products

- Granules

- MOD - Terra product

- MYD - Aqua product

- Granule - A 5 minute piece of an orbit

- Granules

## Level 1 Products   MOD021KM - 1KM calibrated geo-located radiances   MOD02HKM - .5 KM calibrated geo-located radiances	   Bands                Nm             Name  	       3		459-479          .47	                         4	             545-565          .55     	        5	           1230-1250       1.2                     6	           1628-1652       1.6	        7	           2105-2155       2.1   MOD02QKM -   .25 KM calibrated geo-located radiances               Bands                Nm             Name                      1		620-660           .66                  2                841-876          .87       http://www.mcst.ssai.biz/mcstweb/L1B/product.html

## http://www.mcst.ssai.biz/mcstweb/L1B/product.html

- _[http://www.mcst.ssai.biz/mcstweb/L1B/product.html](http://www.mcst.ssai.biz/mcstweb/L1B/product.html)_

- Level 1 Products

## MODIS 

- Atmosphere Processing Flow Chart

- Level 0

- Level 1

- Instrument Packet Data

- MOD 01
- Level 1A

- MOD 02
- Calibrated Radiances
- Level 1B

- MOD 03
- Geolocation Data Sets

## Organization of the MODIS DATA   MOD - Terra product   MYD - Aqua product   Granule - A 5 minute piece of a MODIS orbitLevel 1 Products (granule)   

- MOD02  Level 1B Calibrated geo-located radiancesMOD03  1Km Geolocation Fields

## Formatting of MODIS products

- All MODIS products come in HDF format.
- In HDF format each file contains both data and metadata
- SDS - Each parameter within a MODIS HDF file is referred to as an SDS
- (Scientific Data Set)
- An SDS must be referenced precisely according to name when analyzing the data
- with your own computer code.

## MOD04   Aerosol MOD06   CloudMOD05   Water VaporMOD07   Atmosphere ProfileMOD35   Cloud MaskMODATML2   Joint Product

- MODIS LEVEL II PRODUCTS

- Geophysical parameters derived from MODIS radiances

## Collection refers to a coherent grouping of the data.  

- A collection is usually processed by the same set of algorithms

- Aqua (MYD) products are currently collection 5.  They willbe reprocessed to collection 5.1 beginning in MayTerra (MOD) products are collection 5.  Reprocessing to    collection 5.1 will begin after Aqua is completed.

- Changes in the calibration of the instrument may coincide withcollection updates but are not integrated into algorithm changes.

- Reprocessing: Applying the same set of algorithms to the wholedata set.Forward Processing: Applying the current algorithm to newlyacquired data.

**A few important terms for level 2 and 3 derived products**

## MODIS Level II Products

- MOD04   Aerosol
- The Aerosol Product monitors aerosol type, aerosol optical thickness, particle size distribution, aerosol mass concentration, optical properties, and radiative forcing.
- MOD06   Cloud
- The Cloud Product monitors the physical and radiative properties of clouds including cloud particle phase (ice vs. water, clouds vs. snow), effective cloud particle radius, cloud optical thickness, cloud shadow effects, cloud top temperature, cloud top height, effective emissivity, cloud phase (ice vs. water, opaque vs. non-opaque), and cloud fraction under both daytime and nighttime conditions.
- MOD05   Water Vapor
- The Water Vapor Product monitors atmospheric water vapor and precipitable water.
- MOD07   Atmosphere Profile
- The Atmosphere Profile Product monitors profiles of atmospheric temperature and moisture, atmospheric stability, and total ozone burden.
- MOD35   Cloud Mask
- The Cloud Mask Product indicates whether a given instrument field of view (FOV) of the Earth's surface is unobstructed by clouds or affected by cloud shadows. The cloud mask also provides additional information about the FOV including the presence of: cirrus clouds, ice/snow, and sunglint contamination. Finally flags denoting day/night and land/water are included.

- _[http://modis-atmos.gsfc.nasa.gov/products](http://modis-atmos.gsfc.nasa.gov/products)_

## MODIS Level II Products - continued

- MODATML2  Joint Product - contains a spectrum of key parameters gleaned from the complete set of standard at-launch Level 2 products: Aerosol, Water Vapor, Cloud, Profile, and Cloud Mask. The Joint Atmosphere product was designed to be small enough to minimize data transfer and storage requirements, yet robust enough to be useful to a significant number of MODIS data users.  Data are stored at 5-km and  10-km (at nadir) spatial resolutions.

## Level 3 - Where all atmospheric products come together

- _[http://modis.gsfc.nasa.gov/data/dataprod/pdf/MOD_08.pdf](http://modis.gsfc.nasa.gov/data/dataprod/pdf/MOD_08.pdf)_

- 1 degree resolution, so products are averaged from
- their native retrieval resolution.
- Averaging is either straightforward or weighted by
- QA flag.
- Daily
- 8-Day
- Monthly averages available.

- Note that one grid square can contain multiple orbits.
- Level 3 is not synchronous in time!

## Level 2 Aerosol Product

- (AOD)

- Level 3 Aerosol Product
- (AOD)

## Daily L3 aerosol optical thickness over land and ocean

-  The large gaps over ocean are due to Sunglint
-  The gaps over land are due to bright surfaces and
-   gaps due to cloud systems.
-  Regularly spaced gaps near the equator are due
-  to lack of coverage between orbits.

## Daily Level 3

- MOD08_D3

- Cloud optical thickness

- Cloud top
- pressure

- Gaps due to
- No clouds

## Cloud optical

- Properties
- Come with an
- Estimate of the
- Errors for each
- retrieval

## Daily

- 8 day

- Monthly

- Daily = MOD08_D3
- 8-day = MOD08_E3
- Monthly =MOD08_M3

- Less missing data
- with increasing time interval!

## Level 3

- Also comes with an array of statistics:
- Means, standard deviations, max and min retrieval
-    in each grid box.
- Histograms and joint histograms between products.
- Number of pixels that went into the mean of
-    each grid box

## Organization of the MODIS DATA   MOD - Terra product   MYD - Aqua product   Granule - A 5 minute piece of a MODIS orbitLevel 1 Products (granule)      Level II Products (granule)    Level III Products (global)      

- Geophysical parameter derived from MODIS radiances

- Organization of the MODIS DATA   MOD - Terra product   MYD - Aqua product   Granule - A 5 minute piece of a MODIS orbitLevel 1 Products (granule)      Level II Products (granule)    Level III Products (global)

- MOD02  Level 1B Calibrated geo-located radiancesMOD03  1Km Geolocation Fields

## ReferencesAll things MODIS atmosphere products:http://modis-atmos.gsfc.nasa.govMODIS Level 1 Products Descriptionhttp://www.mcst.ssai.biz/mcstweb/L1B/product.htmlMODIS Level II Products Descriptionhttp://modis-atmos.gsfc.nasa.gov/products.htmlDetailed description of the aerosol product and a link to the ATDBwhich describes the aerosol algorithms in detail.http://modis-atmos.gsfc.nasa.gov/MOD04_L2/index.html

## Slide 21

## Understanding a MODIS File Name

- MOD04_L2.A2001079.0255.005.2006289012028.hdf