Summer Melt of McMurdo Ice Shelf from Satellite Data: 2013-2019

Using Landsat 8 imagery, a six-year tendency (2013-2019) of the melt percentage of the McMurdo Ice Shelf is developed based on Normalized Difference Water Index Ice. The water pixels are mapped using an index value of 0.12 and above. The summer melt season is defined as the period of October 1st – February 28th, when liquid surface melt water presents. The retrieved melt water percentages are then compared with the daily mean and daily maximum of air temperature and solar irradiance, to determine if a possible correlation existed. The air temperature data are from automated weather stations recorded at ice runways located directly on the McMurdo Ice Shelf. Solar irradiance data (280-600 nm) are from National Oceanic and Atmospheric Administration’s Antarctic UV Monitoring Network.

It is found that four of the six years when analyzed individually showed no correlation between melt water percentage with either daily averaged temperature or daily averaged solar irradiance, except for two years with good correlations: R2 of 0.80 (2013-2014 season) and 0.72 (2015-2016 season), at 99% significant level. The results are similar when daily maximum temperature or daily maximum solar irradiance are used for the analysis. A multiple regression for all six years combined produces a low correlation of 0.16 for both averaged and maximum daily temperatures and solar irradiance, but at 99% significant level.

Additionally an overall slight decrease tendency for each of the three variables (temperature, solar irradiance, and melt water percentage) during the cloudless days of the study period is found. A slight increasing tendency for solar irradiance, with a slight decreasing tendency for temperature is found when the entire season data is taken into account for both daily averaged and daily maximum variables.