Landsat Known Issues

Landsat 8 OLI Lower Truncation

Landsat data are systematic, geometric, radiometric, and terrain corrected to provide the highest quality data to the user communities. Occasionally, anomalies occur and artifacts are discovered that require research and monitoring. 

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The detectors of the Landsat 8 OLI can register 14 bits of data. However, only the upper or lower 12 bits are transmitted from the spacecraft to the ground. During normal operations, the upper 12 bits are transmitted to the USGS ground station to maximize the dynamic range.

On occasion, USGS and NASA calibration and validation engineers submit special requests to acquire some path/rows in the lower truncation mode — meaning that the spacecraft only transmits data to the ground station from the instruments lower 12 bits. Landsat 8 lower truncation acquisitions were made in 2013, 2015, and in 2019 (details are listed below). 

During lower truncation mode acquisitions, regions of high brightness within a scene exceed the lower 12-bit range of 4096 (digital number values per detector), causing the count to begin again using the 13th and 14th bits, which are beyond the lower 12-bit range reported. This causes the numeric values to "roll over" and start counting from zero again. Pixels affected by ‘roll over’ do not correctly reflect the brightness of the Earth’s surface and will visually take on an apparently random value (See example image below).

Example of oversaturated pixels in Landsat 8 Operational Land Imager (OLI) data acquired in lower truncation

Example of oversaturated pixels in Landsat 8 Operational Land Imager (OLI) data acquired in lower truncation, with lower 12 bits only. 

These roll over values are not differentiated from valid values elsewhere in the image. More so, the cloud information in the Landsat 8 OLI Quality Assessment Band is unreliable.

NOTE: Data acquired in lower truncation mode are available for download from EarthExplorer, and while most cloud free acquisitions will not be affected by the lower truncation mode setting, users should use caution if using these images for operational activities. The metadata field SENSOR_MODE indicates "TRUNCATION_OLI = "LOWER" for these scenes. 

2013

In 2013, 440 scenes were acquired during Landat 8's on-orbit checkout period prior to data becoming available to all users.  This file lists the scenes acquired in lower truncation mode. 

2015

In 2015, the scenes acquired were used to investigate the value of the lower two bits and support the possibility of downloading all 14 bits of data for Landsat 9. Data to support two studies were acquired: 1) a night interval through the western United States over fires and urban areas, and 2) a day interval off the coast of eastern Australia over dark water. The artifacts are most noticeable over fires in the night data and over clouds in the day data.

2015 Lower Truncation Mode Acquisitions
Path / Rows Dates Area
Path 139, Rows 202 to 217 8/22 (DOY 234)
9/7 (DOY 250)
9/23 (DOY 266)
Western United States:  nighttime acquisitions covering  San Diego, Los Angeles, 
Lake Tahoe, Portland, Mount St. Helens, Mount Hood, 
Mount Adams, Mount Adams Wildfire, Seattle, Mount Rainer
Path 88, Rows 75 to 84 9/1 (DOY 244)
9/17 (DOY 260)
10/3 (DOY 276)
Eastern Australia: dark water coastal acquisitions covering  Coastal Australia Cato Reef 

2019

From September to December 2019, a number of scenes are being acquired in lower truncation mode. The dates and affected paths are listed below. Specific rows for each path will be added when the exact acquisition schedules are received.

2019 Lower Truncation Mode Acquisitions
September 2019 October 2019
9/12-DOY 255: Path 24 Rows 244-248, Path 40 Rows 001-002
9/17-DOY 260: Path 27 Rows 246-248, Path 43 Rows 001-036 
9/19-DOY 262: Path 25 Rows 247-248, Path 41 Rows 001-038
9/26-DOY 269: Path 42 Rows 001-037
9/28-DOY 271: Path 40 Rows 001-003
10/3-DOY 276: Path 43 Rows 001-036                                          
10/5-DOY 278: Path 41 Rows 001-038
10/12-DOY 285: Path 42 Row 001
10/14-DOY 287: Path 40 Row 001
10/19-DOY 292: Path 43 Row 001
10/21-DOY 294: Path 41 Row 001
10/28-DOY 301: Path 42 Row 001
10/30-DOY 303: Path 40 Row 001
November 2019 December 2019
11/4-DOY 308: Path 43 Row 001
11/6-DOY 310: Path 41 Row 001
11/13-DOY 317: Path 42 Row 001
11/15-DOY 319: Path 40 Row 001
11/20-DOY 324; Path 43 Row 001
11/22-DOY 326: Path 41 Row 001
11/29-DOY 333: Path 42 Row 001
12/1-DOY 335: Path 40 Row 001
12/6-DOY 340: Path 43 Row 001
12/7-DOY 341: Path 42 Row 001
12/15-DOY 349: Path 42 Row 001
12/17-DOY 351: Path 40 Row 001
12/22-DOY 356: Path 43 Row 001
12/24-DOY 358: Path 41 Row 001