Landsat-7 Satellite705-km altitude16-day repeat cycle185 km swath widthDescending node at 10:00 - +15 min.Whisk-broom scannerRadiometric resolution: 28 (256 levels)

ETM+ sensor30-m XS (for 6 bands) & 60-m thermal15-m pan bandImage data (185 km by 185 km)$475 raw data; $600 corrected dataNASA developing a global archive of ETM+Web sites:http://landsat7.usgs.govhttp://earthexplorer.usgs.govLandsat-7 Satellite

Electromagnetic SpectrumRemote sensing images are taken within specific spectral regions

Landsat-7 coverage over Ohio

GIS dataRemote sensingIntegrated Solution For Geospatial Data164.107.56.100Landsat-7 & Geospatial Data BaseProvide Data for Research & Education

Ikonos 4-mLandsat-7 ETM+ 30-mOSU Campus

Ikonos 4-m XS

1984 Land Use Map path 19/row 32Water: 249.43 km2Urban: 1348.53 km2Forest: 10700.92 km2Agriculture: 17780.62 km2Pasture: 175.50 km2Grass: 2609.45 km2

1999 Land Use Map path 19/row 32Water: 268.74 km2Urban: 2312.35 km2Forest: 11182.39 km2Agriculture: 16675.65 km2Pasture: 1308.23 km2Grass: 1518.18 km2

Urban Area Change from 1984-1999 path 19/row 32

Landuse

1984(km2)

1999(km2)

Change %

Ashland

Urban

25

52

35.7

Ashland

Agriculture

504

479

-2.6

Crawford

Urban

26

43

24.9

Crawford

Agriculture

723

804

5.3

Delaware

Urban

42

98

40.5

Delaware

Agriculture

707

657

-3.6

Fairfield

Urban

36

94

44.5

Fairfield

Agriculture

737

660

-5.5

Franklin

Urban

411

685

25.0

Franklin

Agriculture

613

410

-19.8

Holmes

Urban

17

47

46.4

Holmes

Agriculture

403

385

-2.3

Knox

Urban

17

37

37.1

Knox

Agriculture

658

626

-2.5

Licking

Urban

54

102

31.2

Licking

Agriculture

858

725

-8.4

Madison

Urban

22

37

25.0

Madison

Agriculture

898

1017

6.2

Marion

Urban

44

64

18.3

Marion

Agriculture

743

819

4.9

Morrow

Urban

12

22

31.2

Morrow

Agriculture

615

662

3.7

Perry

Urban

14

26

32.0

Perry

Agriculture

366

224

-24.0

Richland

Urban

47

73

21.5

Richland

Agriculture

587

594

0.6

Union

Urban

30

42

17.1

Union

Agriculture

792

849

3.5

Wayne

Urban

77

106

15.8

Wayne

Agriculture

715

751

2.4

Wyandot

Urban

27

69

44.7

Wyandot

Agriculture

784

787

0.2

Landsat-7 Band 1: Blue Sandusky Bay 23 March 2001

Landsat-7 Band 4: Near Infrared Sandusky Bay 23 March 2001

Landsat-7 Sandusky Bay 23 March 2001

OhioViewArchive of Landsat-7 images http://www.ohioview.org/

SeaWiFS Comparison to AVHRR SeaWiFSSpatial Resolution : 1.1 km (LAC), 4 km (GAC)Radiometric Resolution: 210Spectral Resolution:6 visible bands, 20 nm wide2 near IR bands, 40 nm wideAVHRRSpatial Resolution : 1.1 km (LAC), 4 km (GAC)Radiometric Resolution: 210Spectral Resolution:0.58 - 0.68 m (visible)0.72 - 1.10 m (near IR)3.55-3.93 m (thermal)10.5 - 11.5 m (thermal)

SeaWiFS ImageAugust 27, 1998555 nmAVHRR ImageAugust 27, 1998Channel 2SeaWiFS Comparison with AVHRR

SeaWiFS ImageAugust 16, 1998555 nmGLFS Vertical Integrated VelocityAugust 16, 1998SeaWiFS Comparison with AVHRR

Level 2 SeaWiFS Product CreationLevel 1 SeaWiFS Image Obtained From NASAAncillary DataCalibration TableOC-2 Chlorophyll AlgorithmLevel 2 SeaWiFS Product for Chlorophyll

SeaWiFS Level 2 Image for Chlorophyll Concentration Chlorophyll concentration color coded uniformly for all products

July 5, 1998July 11, 1998

August 16, 1998August 29, 1998

September 3, 1998September 10, 1998

September 18, 1998September 29, 1998

October 12, 1998October 21, 1998

This slide show a comparison between the SeaWiFS sensor and the AVHRR sensor. You can see the two sensors have matching spatial resolution - 1 km- and radiometric resolution - 210 or 1024 gray levels. The spectral resolution differs between the two sensors. First, SeaWifs has 6 visible bands, whereas AVHRR has only 1. This allows us to spectrally separate out water properties such as suspended sediment at various depths and chlorophyll absorption. For these 6 band they are 20 nm wide, whereas the AVHRR visible band is much wider at 100 nm wide. One advantage that AVHRR has 2 thermal bands, whereas SeaWiFS only has the near IR bands.This slide shows an image comparison between a Band 4 SeaWifs Image (490-530 nm) and a Channel 1 (580 - 680 nm) AVHRR image of Lake Erie. Notice that patterns of suspended sediment are shown in much greater detail in the SeaWiFS image. Particularly, notice the detail of the swirling pattern towards the eastern end of the lake. This is a suspended sediment plume being driven offshore from Long Point. The pattern can be seen branching out in the SeaWiFS image, whereas in the AVHRR image the pattern shows very little swirling detail. At the SeaWiFS wavelengths, the light is penetrating deeper into the water column, allowing us to see more details of the suspended sediment patterns.This slide also shows a comparison between the SeaWIFS 510 nm image and the corresponding Great Lakes Forecasting System estimation of Vertical Integrated Velocity patterns for Lake Erie. Similarities are most visible in the central basin of the lake where detailed patterns in the SeaWiFS image corresponding to eastward flowing velocities of 0.2 - 0.3 m/hr.This slide show how a SeaWiFS level 2 product is generated. To create the level two product, Level 1 imagery is obtained from NASA and imported into a custom SeaWiFS image processing software package: SeaDAS. Once the image data has been imported to SeaDAS, it is combined with ancillary data consisting of ozone and meteorological files and a calibration table. This data combination is then run through the OC-2 algorithm to produce the Level 2 Product. The level two product contains a number of data layers; here we will discuss the chlorophyll concentration image.This image is a typical Level 2 product showing the chlorophyll concentration of the entire lake. The color bar shown to the right is uniform for all Level 2 products. The product shows chlorophyll concentration ranging from 0 mg/m3 for black, 0.01 to 0.1mg/m3 for violet to blue, 0.1 to 1 mg/m3 for blue to green, 1.0 to 10 mg/m3 for green to yellow, and 10 to 64 mg/m3 for yellow to red.These are the first two images in a series of images created to track the development of a microcystis boom that occurred in lake Erie during the late summer/early fall in 1998. On July 5, the lake appears almost uniformly green without any significant areas of algae. The next image on July 11 shows the beginning of the bloom in the western portion of the lake, revealed by the areas of red corresponding to high chlorophyll concentrations of approximately 64 mg/m3.The August 16 image shows the western portion of the lake becoming a more increasingly red from the previous image. This trend continues into the August 29 image, showing the increase in size of the bloom with time.These images show the bloom expanding eastward into the center of Lake Erie. Notice that as the bloom expands, the dense areas of the bloom in the eastern basin begin to dissipate.These images show the bloom continue to expand eastward and also show the continually diminishing in density. These images show the bloom finally subsiding nearly four months after it was initially detected. Notice that this is already October, the beginning of Autumn and the cooling of the lake.