THIRN4L1CH115 is the Nimbus-4 Temperature-Humidity Infrared Radiometer (THIR) Level 1 Meteorological Radiation Data at 11.5 microns product and contains radiances expressed in units of equivalent brightness temperature measured in the 10.5 - 12.5 (11.5) micron channel. The data, originally written on IBM 360 machines, were recovered from magnetic tapes, also referred to as Nimbus Meteorological Radiation Tapes (NMRT-THIR). The data are archived in their original IBM 36-bit word proprietary format, also referred to as a binary TAP file. The Nimbus-4 satellite was successfully launched on December 11, 1972. The THIR experiment on Nimbus-4 replaced the measurements made by the HRIR and MRIR instruments flown on previous Nimbus satellites. The THIR instrument is a two channel high resolution scanning radiometer designed to perform two major functions: The 11.5 micron channel provides both day and night cloud top or surface temperatures. The ground resolution at the sub-point is 8 km and operates day and night. The 6.7 micron channel gives information on the moisture content of the upper troposphere and stratosphere and the location of jet streams and frontal systems. The water vapor channel has a resolution of the sub-point is 22 km and operates mostly at night. The THIR Principal Investigator was Andrew W. McCulloch from NASA Goddard Space Flight Center. The Nimbus-4 THIR data are available from April 13, 1970 (day of year 103) through April 1, 1971 (day of year 91). The THIRN4L1CH67 product contains the 6.7 micron channel data. This product was previously available from the NSSDC with the identifier ESAD-00004 (old ID 70-025A-02D).