GOES/POES: Estado, órbitas y productos

Presentación del tema: "GOES/POES: Estado, órbitas y productos"— Transcripción de la presentación:

1 GOES/POES: Estado, órbitas y productos
Dra Bernadette Connell CIRA/NOAA-RAMMT Versión en español: Dra. Vilma Castro Marzo 2005

2 Esquema de la presentación
GOES vs. POES GOES Satélite y sensores Orbita Horario de las imágenes Canales y productos (imágenes y sondeos) POES Disponibilidad de imágenes Canales y productos

3 ¿Porqué queremos saber esto?
Para conocer los recursos disponibles actualmente o qué recursos estarán disponibles en el futuro Para ayudar a entender características importantes de los diversos satélites Para saber cuándo esperar ver imágenes Definir qué está sucediendo cuando no hay imágenes.

4 GOES vs. POES 850 km Geostationary Operational Environmental Satellite órbita geo-sincrónica a 35,800 km de altura Polar-orbiting Operational Environmental Satellite órbita sincronizada con el sol a 850 km de altura 35,800 km NOAA series orbits: 833 +/- 19 km or 870 +/- 19 km

5 Los sistemas GOES y POES
Mediciones ambientales: Adquirir, procesar y diseminar imágenes y sondeos. Monitorear entorno espacial Recolección de datos: Interrogar y recibir datos de plataformas de terrestres de recolección de datos Difusión de los datos: Retransmitir continua de reportes via facsímil del tiempo y de otros datos meteorológicos a pequeños usuarios Retransmitir mensajes de ayuda de naves aéreas o marinas a estaciones terrestres de búsqueda y rescate The DCS/2 from NOAA KLM supplements the GOES data collection system in collecting both the information from the more-northern and more-southern latitudes and the location data on free-floating transmitters. GOES I-M DataBook, NOAA KLM User’s Guide

6 Características del GOES
Observa eventos y su evolución Repite la cobertura en minutos (t = 15 o 30 min o menos) Cobertura de todo el disco terrestre Visión restringida de latitudes altas debido al ángulo; visión excelente de los trópicos Mismo ángulo de visión para puntos fijos Iluminación solar cambiante para puntos fijos a lo largo del día Resolución: visible – 1 km , IR 4 km sondeos – 10 km Visión continua ayuda a tener un campo de visión claro para los sondeos Sensores pasivos Viewing clouds at higher latitudes (large distances away from the satellite subpoint) from a geostationary orbit introduces a significant parallax error. Unless directly above the satellite subpoint, higher clouds appear displaced from their true ground locations. The displacement is away from the satellite subpoint, and can be greater than the height of the cloud. Satellite Meteorology: Remote Sensing Using the New GOES Imager

7 Características del POES
Observa eventos a horas fijas poco frecuentes Repite su cobertura dos veces al día (t =12 hr) Cobertura global Visión excelente en todas las latitudes Angulo de visión variable Misma iluminación solar siempre Resolución: visible – 1 km, IR – 1 km sondeos: microonda – km, IR - 20 km Las microondas permiten mediciones atmosféricas y del suelo en presencia de nubes Sensores pasivos y activos The parallax error for polar satellites becomes significant only at extreme viewing angles away from nadir (greater than 45 degrees or 1000 km from satellite subpoint). Satellite Meteorology: Remote Sensing Using the New GOES Imager

8 Resolución de la imagen
El diseño del sensor y la resolución de la imagen está determinada por muchos factores: Detalle en la horizontal (imágenes) Detalle en la vertical (sondeos) Distancia del satélite al suelo (36,000 km vs. 850 km) Poder de resolución del lente y longitud de onda de la radiación. Tamaño del sensor (costo) Microwave instruments have to date only been deployed on polar-orbiting spacecraft because large antennas are needed to observe earth-emitted energy at the very long wavelengths associated with microwaves.

9 Sensores activos vs. pasivos
Un sensor pasivo mide la energía emitida por una fuente. Un sensor activo, como el radar, mide la señal de retorno de un pulso de energía emitido por el sensor.

10 Multiespectral vs. Hiperespectral
Sensores Multiespectrales – forman imágenes en un número reducido de bandas anchas del espectro Sensores Hiperespectrales – forman imágenes en un gran número (cientos) de bandas contiguas y estrechas del espectro

11 El satélite GOES The GOES Spacecraft GOES I-M DataBook

12 Area Scan Imager (For GOES 8 – 11)
GOES-12 has a wider spectral band for the water vapor channel and the 12.0 um channel has been replaced with a 13.3 um channel. GOES I-M DataBook

13 Los canales del GOES Canal Long de onda Long de onda Número de Resolución (µm) central (µm) detectores (por barrido) (km) _________________________________________________________ Visible Shortwave IR 3 G 6 G Longwave IR

14 GOES – Canales de sondeo
Centro long.de onda (um) Comentario (región espectral, aplicación) 1 14.71 CO2, Temperatura estratosférica 10 7.43 Vapor de agua. Humedad troposfera baja a media 2 14.37 11 7.02 Vapor de agua. Humedad troposfera media 3 14.06 CO2, Temperatura troposfera alta 12 6.51 Vapor de agua. Humedad troposfera alta 4 13.96 CO2, Temperatura troposfera media 13 4.57 CO2, Temperatura troposfera baja 5 13.37 14 4.52 6 12.66 Vapor de agua, humedad troposfera baja 15 4.45 7 12.02 Vapor de agua, ventana “sucia” (contaminada con humedad) 16 4.13 CO2, Temperatura de la capa límite 8 11.03 Ventana, temperatura de suelo y nubes 17 3.98 9 9.71 Ozono, ozono estratosférico 18 3.74 Visible 0.94 Ventana en el rango visible, temperatura de suelo y nubes Onda media Onda larga Onda corta The sounder has 19 channels, point out the resolution at nadir. Point out the various absorption regions and the applications. Onda media Resolución = 10 km en el nadir Satellite Meteorology: Using the GOES Sounder

15 GOES GOES I-M DataBook

16 RUTINA DEL GOES-ESTE, IMAGENES HORARIO DE SECTORES
Essentially: CONUS in conjunction with S. Hemis. every 30 minutes Alternates with N. Hemis. EXT. every 30 minutes Every 3 hours there is a full disk (for GOES E it starts at xx:45) NESDIS Office of Satellite Operations: SECTOR DURACIÓN MINS:SECS CONUS :48 N. HEMIS. EXT :13 S. HEMIS :48 DISCO :05

17 GOES-ESTE IMAGENES BARRIDO RAPIDO HORARIO DE SECTORES
Essentially 2 CONUS, N. Hemisphere, 1 CONUS, S. HEMIS. S.S., 2 CONUS, N. Hemisphere, CONUS Every 3 hours there is the full disk. SECTOR DURACION MINS:SECS CONUS :43 N. HEMISPHERE : S. HEMIS. S. S :45 DISCO :05

18 GOES-ESTE IMAGENES BARRIDO SUPER RAPIDO HORARIO DE SECTORES
Essentially for each hour: 8 SRSO, N. Hemisphere, SRSO, CONUS, 8 SRSO, N. Hemisphere, SRSO, CONUS SECTOR DURACION MINS:SECS CONUS :43 N. HEMISPHERE :44 SRSO (Maryland) :02 DISCO :05

19 GOES-ESTE SONDEO HORARIO DE LOS BARRIDOS
The CONUS sector occurs every hour. The E. Caribbean, Gulf of Mexico, and N. Atlantic Sectors alternate with the CONUS sector: E. Caribbean (1 every 6 hrs.), N. Atlantic (1 every 6 hrs), then 4x Gulf of Mexico (off 2 hrs, on 4 hrs. except at end of day only 3 hrs.) SECTOR DURACIÒN MINS:SECS CONUS :00 CARIBE ESTE :00 GOLFO DE MEXICO :00 N. ATLANTIC :00

20 Productos del GOES - imágenes
Vientos Precipitaciones extremas Niebla, nubes bajas Engelamiento en vuelo Tomorrow (Wednesday), Dr. Purdom will talk about the GOES imager channels. Besides the individual channels, there are also products that are produced from either individual channels or combination of channels. We’ll be talking about many of these products throughout the course. Detección de ceniza Detección de incendios

21 Sondeos del GOES Derivados: Productos en imágenes (DPI)
Lifted Index CAPE Inhibición de la convección Total de agua precipitable These when you know the temperature and moisture profiles, you can derive the products. If time, add Microburst products ( Other new products! ( The CAPE product displayed is an atmospheric stability parameter for a given vertical thermodynamic profile, which indicates the amount of positive (buoyant) energy available to an idealized parcel, ascending from the Level of Free Convection (LFC) to the Equilibrium Level (EL). The larger the value (or the "positive-energy area" under the parcel curve on a thermodynamic diagram), the more unstable would the atmosphere be. A CAPE of 1500 J/kg would indicate a modestly unstable airmass. The values are color-coded with brown/beige>blue>yellow at the more stable end while red>magenta/purple would indicate considerably more potential instability. (Note that transitions between colors beige/blue/yellow/red/magenta occur at CAPE values of 1000, 2000, 3000, and 4000 J/kg respectively). This enhancement table is experimental and suggestions for improvement are welcome. A time sequence of the images remains the best way to monitor stability trends. Temperatura de las superficies Viento derivado del canal del vapor de agua

22 POES Main Operational POES: NOAA DMSP Semi-operational POES: QuikSCAT
Terra and Aqua (contain MODIS imager)

23 NOAA KLM System Sensors of interest
Advanced Very High Resolution Radiometer/3 (AVHRR/3) Advanced Microwave Sounding Unit – A (AMSU – A) Advanced Microwave Sounding Unit – B (AMSU – B) High Resolution Infrared Radiation Sounder (HIRS/3)

24 Defense Meteorological Satellite Program (DMSP)
Sensors of interest Special Sensor Microwave / Imager (SSM/I) Special Sensor Microwave / Temperature (SSM/T) – Atmospheric Temperature Profiler SSM/T2 – Atmospheric Water Vapor Profiler Microwave energy is referred to at various "frequencies" as opposed to "wavelengths." This terminology is commonly used by the remote sensing community. Orbit – 860 km

25 Cross-track Scanning (AVHRR, AMSU, MODIS)
The AVHRR and AMSU are cross-track scanning instruments. The best resolution is at nadir with coarser resolution out to the sides. The AMSU is a cross-track scanning instrument, sweeping out a line of FOVs perpendicular to the satellite's orbital track. The schematic shows that the AMSU scans to a maximum of +/ degrees from nadir resulting in an orbital swath approximately 2200 km wide. (The AVHRR scans to a maximum of 55.3 degrees from nadir resulting in an orbital swath approximately 3000 km wide.) The composite of AMSU TPW swaths from descending NOAA-15 orbits shows that this scanning leaves narrow gaps equatorward of 30 degrees north/south latitude. Polar Satellite Products for the Operational Forecaster – COMET CD Module

26 Conical Scanning –SSM/I
The SSM/I is a conical scanning instrument, sweeping out consecutive 102-degree arcs perpendicular to the satellite's orbital track. The schematic shows that this results in an orbital swath approximately 1400 km wide, 64 percent of the swath of the AMSU. Polar Satellite Products for the Operational Forecaster – COMET CD

27 Orbital Coverage The AVHRR is a scanning radiometer – it makes calibrated measurements of upwelling radiation from small areas that are scanned across the sub-satellite track. Ground resolution at the end of scan is 2.3 x 6.4 km. The scan line angle from nadir is +/ deg. And the distance is +/ km. Orbit of 850 km. Satellite makes one orbit (360°) in about 100 min; i.e., it goes about 3.6°/min, or about 10° in 3 minutes. With a knowledge of which way the satellite is moving and how fast it is moving, one can estimate viewing time at a particular point. Introduction to POES data and products – COMET/VISIT teletraining

28 AMSU coverage (2200 km swath)
The AMSU orbital swath is approximately 2200 km wide. The composite of AMSU TPW swaths shows that this scanning leaves narrow gaps equator ward of 30 degrees north/south latitude. Example image from Stan Kidder’s AMSU webpage at CIRA:

29 SSMI coverage (1400 km swath)
Example from NOAA’s Marine Observing Systems Team Web Page

30 Ground Resolution (at nadir) (km)
AVHRR/3 (3000 km swath) Channel Spectral Range (um) Ground Resolution (at nadir) (km) Application 1 1.09 Clouds, land-water boundaries, snow, ice, vegetation monitoring 2 3A Clouds, sea surface temperature 3B 4 5 The AVHRR is a scanning radiometer – it makes calibrated measurements of upwelling radiation from small areas that are scanned across the sub-satellite track. Ground resolution at the end of scan is 2.3 x 6.4 km. The scan line angle from nadir is +/ deg. And the distance is +/ km. Orbit of 850 km. Note that the statement, "sun synchronous", used to describe the TIROS-N orbit is an approximation. In reality, the orbit precesses in an effort to maintain the same local time. Thus, over a 14-day cycle the actual local time varies slightly. Besides the variation in nominal equatorial crossing times and the annual variation in sunrise and sunset, there is a tendency for actual equatorial crossings to occur somewhat later during the lifetime of any given satellite. This change is several minutes monthly, amounting to as much as two hours over the lifetime of a satellite. Also, is should be observed that the polar orbit of the satellite, combined with the 3000-km swath of the AVHRR, leads to considerable overlap of the satellite imagery at polar latitudes. At equatorial latitudes the orbit is designed so that only a few kms overlap on adjacent orbits, but at 80 degrees N/S the sequential AVHRR swaths overlap by about one-third. This greatly increases the coverage at polar latitudes which is important for the removal of clouds in this persistently cloudy region of the world. Info From: The Advanced Very High Resolution Radiometer (AVHRR): A Brief Reference Guide by David A. Hastings and William J. Emery Channels 1 and 2 were to be used to discern clouds, land-water boundaries, extent of snow and ice, and the inception of snow/ice melting, and to monitor terrestrial vegetation employing the computation of the NDVI; Channels 3, 4, and 5 were to be used to measure the temperature of clouds and the sea surface, and for nighttime cloud mapping. Applications have extended far beyond these original objectives. The list of applications is much longer – this is a sample.

31 AVHRR Products Sea Surface Temperature (SST)
Normalized Difference Vegetation Index (NDVI) Atmospheric aerosols Volcanic Ash detection Fire detection NDVI Aerosols Sea Surface Temperature (SST) – gridded fields: daily 100-km (Global-Scale Analysis), bi-weekly 50 km (Regional Scale Analysis), biweekly 14 km (Local Scale) NDVI is used to derive vegetation condition. Good reference for products from the Office of Satellite Data Processing and Distribution: (That’s where I got pictures for the first 3 products.) The fire image was obtained from the United States Department of Agriculture Forest Service Site that produces AVHRR Satellite Images: The volcanic ash image was ‘borrowed’ from the tutorial: Polar Satellite Products for the Operational Forecaster Fires Volcanic Ash

32 AMSU-A AMSU-B Frequencies (GHz) Channel and Polarizations 1 23.8 R
4 52.8R /- 3R 5 53.6R /- 7R 6 54.4R 7 54.9R 8 55.5R 9 57.2R 10 /- .217R 11 / /- .048R 12 / /- .022R 13 / /- .010R 14 / / R 15 Notation: x±y±z; x is the center frequency. If y appears, the center frequency is not sensed, but two bands, one on either side of the center frequency, are sensed; y is the distance from the center frequency to the center of the two pass bands. If z appears, it is the width of the two pass bands. Polarization: R = rotates with scan angle. Microwave energy is referred to at various "frequencies" as opposed to "wavelengths." This terminology is commonly used by the remote sensing community. Additional Notation before Polarization: This pattern is easily implemented with radio frequency receivers, and it effectively doubles the signal (two pass bands instead of one). Source: Kidder and Vonder Haar (1995)

33 SSM/I – Microwave Imager
Frequency (GHz) Polarization Spatial Resolution 19.35 V, H 43 x 69 km 22.35 V 40 x 60 km 37.0 29 x 37 km 85.5 13 x 15 km The SSM/I is a seven-channel, four frequency, linearly-polarized, passive microwave radiometric system which measures atmospheric, ocean and terrain microwave brightness temperatures at 19.35, , 37.0 and 85.5 GHz. The data are used to obtain synoptic maps of critical atmospheric, oceanographic and selected land parameters on a global scale. The SSM/I archive data set consists of antenna temperatures recorded across a 1,400 km conical scan, satellite ephemeris, earth surface positions for each pixel and instrument calibration. Electromagnetic radiation is polarized by the ambient electric field, scattered by the atmosphere and the Earth's surface and scattered and absorbed by atmospheric water vapor, oxygen, liquid water and ice. The instrument sweeps a 450 cone around the satellite velocity vector so that the Earth incidence angle is always Data are recorded during the of the cone when the antenna beam intercepts the Earth's surface. The channel footprint varies with channel energy, position in the scan, along scan or along track direction and altitude of the satellite. The 85 GHz footprint is the smallest with a 13 x 15 km and the 19 GHz footprint is the largest at 43 x 69 km. Because the 85 GHz footprint is so small, it is sampled twice as often, i.e., 128 times a scan. One data cycle consists of 4 85 GHz scans and 2 scans of the 19, 22 and 37 GHz channels. The complete cycle takes 28 seconds and it must be complete to process the data. SSM/I data are used to derive geophysical parameters; notably, ocean surface wind speed, area covered by ice, age of ice, ice edge, precipitation over land, cloud liquid water, integrated water vapor, precipitation over water, soil moisture, land surface temperature, snow cover and sea surface temperature. Most current methods use statistical algorithms which mean or difference channel brightness temperatures [Hollinger et al., 1989]. Brightness temperatures are computed from antenna temperatures using the published antenna pattern correction which includes dynamic adjustments for antenna side lobe, antenna efficiencies and neighboring pixel contributions. Source: Kidder and Vonder Haar (1995); POES Microwave Applications CD - COMET Polarization: V = vertical, H = horizontal Source: Kidder and Vonder Haar (1995); POES Microwave Applications CD - COMET

34 Meteorological Parameters
Summary of Key Interactions and Potential Uses Frequencies AMSU SSMI Microwave Processes Potential Uses 23 GHz 22GHz Absorption and emission by water vapor Oceanic precipitable water 31, 50, 89 GHz 19, 37, 85 GHz Absorption and emission by cloud water Oceanic cloud water and rainfall Scattering by cloud ice Land and ocean rainfall Variations in surface emissivity: Land vs. water Different land types Differenc ocean surfaces Scattering by snow and ice Land/water boundaries Soil moisture/wetness Surface vegetation Ocean surface wind speed Snow and ice cover We’ll talk more about AMSU in terms of soundings – tomorrow (Wednesday) and in terms of precipitation estimates on Thursday morning Polar Satellite Products for the Operational Forecaster – COMET CD

35 AMSU/SSMI Products Total Precipitable Water (TPW)
Cloud Liquid Water (CLW) Rain rate Snow and Ice cover CLW Example images from Stan Kidder’s AMSU webpage at CIRA: Ice cover Rain rate Snow cover

36 QuikSCAT Orbit: Sun-synchronous, 803 km, 98.6° inclination orbit
Seawinds Instrument: Microwave Radar (active sensor) 13.4 GHz Retrieval of near surface wind speed and direction Resolution on ground: 25 km 1800 km wide swath A scatterometer is a microwave radar sensor used to measure the reflection or scattering effect produced while scanning the surface of the earth from an aircraft or a satellite. This topic will be reviewed on Thursday when we go though Resources and Applications of the VL. Description of the SeaWinds Scatterometer and How It Works: The SeaWinds scatterometer is a microwave radar designed specifically to measure ocean near-surface wind speed and direction. The SeaWinds scatterometer consists of three major parts called subsystems. They are the Electronics Subsystem (SES), the Antenna Subsystem (SAS), and the Command and Data Subsystem (CDS). The Electronics Subsystem is the heart of the scatterometer and it contains a transmitter, receiver and digital signal processor. It generates and sends high radio frequency (RF) waves to the antenna. The antenna transmits the signal to the Earth's surface as energy pulses. When the pulses hit the surface of the ocean it causes a scattering affect referred to as backscatter. A rough ocean surface returns a stronger signal because the waves reflect more of the radar energy back toward the scatterometer antenna. A smooth ocean surface returns a weaker signal because less of the energy is reflected. The echo or backscatter is routed by the antenna to the SES through waveguides (rectangular metal pipes that guide RF energy waves from one point to another). The SES then converts the signals into digital form for data processing. Scatterometery has its origin in early radar used in World War II. Early radar measurements over oceans were corrupted by sea clutter (noise) and it was not known at that time that the clutter was the radar response to the winds over the oceans. Radar response was first related to wind in the late 1960's. The first scatterometer flew as part of the Skylab missions in 1973 and 1974, demonstrating that spaceborne scatterometers were indeed feasible. The Seasat-A Satellite Scatterometer (SASS) ( operated from June to October 1978 and proved that accurate wind velocity measurements could be made from space. A single-swath scatterometer flew on the European Space Agency's Remote Sensing Satellite-1 (ERS-1) mission ( The NASA Scatterometer (NSCAT) ( which launched aboard Japan's ADEOS-Midori Satellite in August, 1996, was the first dual-swath, Ku-band scatterometer to fly since Seasat. From September 1996 when the instrument was first turned on, until premature termination of the mission due to satellite power loss in June 1997, NSCAT performed flawlessly and returned a continuous stream of global sea surface wind vector measurements. Unprecedented for coverage, resolution, and accuracy in the determination of ocean wind speed and direction, NSCAT data has already been applied to a wide variety of scientific and operational problems. These applications include such diverse areas as weather forecasting and the estimation of tropical rain forest reduction. Because of the success of the short-lived NSCAT mission, future Ku-band scatterometer instruments are now greatly anticipated by the ocean winds user community. The NSCAT mission proved so successful, that plans for a follow-on mission were accelerated to minimize the gap in the scatterometer wind database. The QuikSCAT mission ( launched SeaWinds in June 1999. Info taken from the NASA/JPL web pages: NOTE – get to current images from VL entry under satellite products. NASA/JPL web pages:

37 Example from NOAA’s Marine Observing Systems Team Web Page

38 Example from NOAA’s Marine Observing Systems Team Web Page

39 MODIS Moderate Resolution Imaging Spectroradiometer
36 spectral bands 2330 km swath width 55° view angle Resolution on ground at nadir: 1 km for all channels 250 m for bands 1 and 2 (0.645 and um) 500 m for bands 3 – 7 (0.470, 0.555, 1.240, 1.640, um)

40 MODIS Reflective Bands Band Central wavelength (um) Primary Use 1, 2
0.645, 0.865 Land/Cloud/Aerosols Boundaries 3, 4 0.470, 0.555 Land/Cloud/Aerosols Properties 5 – 7 1.240, 1.640, 2.130 8 – 10 0.415, 0.443, 0.490 Ocean Color/ Phytoplankton/ Biogeochemistry 11 – 13 0.531, 0.565, 0.653 14 – 16 0.681, 0.750, 0.865 17 – 19 0.905, 0.936, 0.940 Atmospheric Water Vapor 26 1.375 Cirrus Clouds Emissive Bands 20 – 23 3.750(2), 3.959, 4.050 Surface/Cloud Temperature 24, 25 4.465, 4.515 Atmospheric Temperature 27, 28 6.715, 7.325 Cirrus Clouds, Water Vapor 29 8.550 Cloud Properties 30 9.730 Ozone 31, 32 11.03, 12.02 33 – 36 13.335, , , Cloud Top Altitude

41 MODIS Aqua coverage (2330 km swath)
Space Science and Engineering Center (SSEC)

42 MODIS Products Cloud fraction (daytime) Surface albedo Clear sky precipitable water (IR) Normalized difference vegetation index Cloud optical thickness (water) Ecosystem classification Aerosol optical depth AND MANY MORE

43 MODIS Products Cloud fraction (daytime) Surface albedo Clear sky precipitable water (IR) Normalized difference vegetation index Cloud optical thickness (water) Ecosystem classification Aerosol optical depth AND MANY MORE

44 References CDs produced by the COMET program (see meted.ucar.edu)
Polar Satellite Products for the Operational Forecaster POES Introduction and Background POES Microwave Applications An Introduction to POES Data and Products Satellite Meteorology: Remote Sensing Using the New GOES Imager Satellite Meteorology: Using the GOES Sounder Space Systems Loral, 1996 : GOES I-M DataBook Can be found online at: NOAA KLM User’s Guide NOAA/NESDIS Office of Satellite Operations: NOAA/NESDIS Office of Satellite Data Processing and Distribution Hastings, D. and W. Emery The Advanced Very High Resolution Radiometer (AVHRR): a brief reference guide. Photogrammetric Engineering & Remote Sensing 58(8): Kidder, S.Q., and T.H. Vonder Haar, 1995: Satellite Meteorology. Academic Press, 466 pp. Stan Kidder’s AMSU webpage at CIRA: Defense Meteorological Satellite Program (DMSP) NASA/JPL web pages: NOAA’s Marine Observing Systems Team Web Page MODIS Rapid Response System NASA MODIS Home page