AVHRR Nighttime Weekly and Monthly MCSST Data

The 3 images show valid or interpolated MCSST, and flag data for August 2000. The colors for MCSST data indicate temperatures in degrees Celsius ranging from -2.1( violet), to 17 (green), up to 36 (red), while the colors for flag data show how many observations were available throughout August and used in calculating the monthly MCSST averages. The color bar extending from violet (lowest number, 1)to red (highest number, 7). Ice is grey, land is black and areas for which no date were collected are in white.

Valid Data :

Weekly or monthly averages based on UM/RSMAS weekly MCSST data are given in this first data set. Missing values are indicated by a digital number (DN) of 0, ice values by 254 and land values by 255.

Nighttime Monthly-Averaged Valid MCSST

Interpolated Data :

Weekly or monthly interpolated averages are contained here. These values originally derived from weekly MCSST data computed by the UM/RSMAS. This data set does not have any missing values over open ocean. However, missing values may still exist over large lakes and some small seas. These few remaining missing values are indicated by a DN value of 0. Ice values are indicated by a DN value of 254 and land values by 255.

Nighttime Monthly-Averaged Interpolated MCSST

MCSST Data Interpolation method is described here,

Valid and interpolated MCSST data are provided in the form of DN. Each digital number is a value between 0 and 255. To convert the DN to an SST value in degrees Celsius, use the following equation:

SST (°C) = 0.15 * DN -2.1
Missing Value is set to -2.1 °C
Ice Value is set to 36.0 °C
Land Value is set to 36.15 °C

Flag Data:

The third data set contains the flags and number of observations for the valid MCSST data set. Flag values of 0 indicate missing data. Ice values are represented by 254 and land values by 255. Values greater than 0 and less than 254 represent the number of valid temperatures used in calculating the weekly or monthly average.

Flag Data

Latitude, Longitude :

These sets include latitude and longitude coordinates for each grid element based on its center. To calculate the latitude and longitude of a grid point, the following equations can be used:

longitude = xgp * dx + (dx/2) - 180.
latitude = (90. - (ygp * dy)) - (dy/2)
xgp = grid point in the x-direction (0 through 719)
ygp = grid point in the y-direction (0 through 359)
dx = 360 deg/720 grid pt = 0.5
dy = 180 deg/360 grid pt = 0.5

Note: Negative signed latitude corresponds to the west and Negative sign by longitude corresponds to the south!

Contact: Dr. Kurt P. Günther