MICRE

Macquarie Island Cloud and Radiation Experiment (MICRE)

1 March 2016 - 31 March 2018

Lead Scientist: Roger Marchand

Observatory: OSC , MCQ

Clouds over the Southern Ocean are poorly represented in present-day reanalysis products and global climate model simulations. Errors in top-of-atmosphere (TOA) broadband radiative fluxes in this region are among the largest globally, with significant implications for modeling both regional and global-scale climate responses. Model TOA radiative errors are largely due to errors in the model representation of clouds and aerosols. However, knowledge of cloud and aerosol properties over the Southern Ocean relies heavily on satellite data sets. Uncertainty in satellite retrievals of cloud and aerosol properties, as well as estimates of surface shortwave and longwave fluxes based on these properties, are especially large for the Southern Ocean. In response to the need for additional measurements of surface radiative fluxes, as well as cloud and aerosol properties over the Southern Ocean, the ARM Climate Research Facility will deploy a variety of ground instrumentation to Macquarie Island, ideally situated at 54.61 degrees south latitude and 158.87 degrees east longitude. It has a small research station operated by the Australian Antarctic Division (AAD) and manned year-round in part by the Australian Bureau of Meteorology (BoM). The Macquarie Island Cloud and Radiation Experiment will be conducted in coordination with AAD and BoM activities planned at this site, specifically deployment of the Collaboration for Australian Weather and Climate Research (CAWCR) millimeter-wavelength cloud radar and the CAWCR cloud and aerosol backscatter lidar. ARM instrumentation is expected to include:

• a set of surface broadband radiometers (sky and ground radiation)
• a microwave radiometer (preferably a three-channel system)
• a ceilometer
• a Multi-Filter Rotating Shadowband Radiometer (MFRSR)
• a precipitation disdrometer
• a sun photometer or other instrument capable of making narrow-band (vis and swir) narrow-field-of-view measurements.

These measurements and associated retrievals will be used to address scientific issues that include evaluating the seasonal cycle of satellite-derived and climate-model-simulated surface radiative fluxes, along with cloud and aerosol properties over the Southern Ocean; and isolating factors that contribute to errors (e.g., errors in assumed or simulated boundary layer structure/moisture, presences of supercooled water). The deployment will be for a two-year period to characterize the full seasonal cycle and its variability.