Atmospheric Boundary Layer

We propose a measurement program designed to characterize the radiational, sensible and latent heat fluxes at the surface, as well as the surface momentum budget (aka wind stress). There are two aspects of the atmospheric forcing measurement strategy: 1. Direct in situ measurements. We will perform direct flux measurements from the ship and drifting ice camps over various ice types and if possible over open leads and/or polynyas. These direct measurements will consist of broadband downwelling shortwave and longwave radiation from the ship and upwelling radiation from the ice during drift periods, conditions permitting. Surface measurements of temperature using IR radiometers and observations of surface characteristics from the ship will enable estimates of upwelling radiation when direct ice measurements are not possible. Sonic anemometers mounted on the ship and, when possible, on the ice floes will provide continuous sensible heat and momentum turbulence measurements. Flow distortion affecting the ship measurements will be assessed and it is likely an inertial-dissipation method will be used for the ship-platform measurement while direct eddy-correlation will be used for the ice-platform measurements. 2. Regional forcing. We will use remotely-sensed and buoy temperature and pressure measurements to characterize regional ice conditions, surface temperature and pressure gradient fields. In addition, Vaisala instrument packages attached to free balloons, tethered streamline balloons, kitoons and kites will measure wind vector, temperature, humidity and pressure as a function of height, particular emphasis on the atmospheric surface and boundary layers. We will use the information obtained from these sources in conjunction with numerical modeling (tuned using the direct measurements described above) to quantify the regional atmospheric forcing during the entire period of the MaudNESS field program. Considerable leveraging of resources will be used to keep costs low for the atmospheric forcing program of MaudNESS. Most of the equipment and data collection systems are already available, the exception being the expendable rawinsonde packages. This will be a joint project between Peter Guest, Naval Postgraduate School and Ian Renfrew, British Antarctic Survey, the latter being provided at no extra cost to NSF. Dr. Renfrew’s funding and, hence, participation is not guaranteed, but considered highly likely if the MaudNESS project occurs.