This project will focus on in situ and remote sensing measurements of wintertime clouds over the Park Range of the Rocky Mountains in northern Colorado. These clouds are generally mixed-phase; the combination of ice, liquid and water vapor presents challenges both to measurements and modeling, and consequently, to understanding their impact on atmospheric radiation and on precipitation. The Colorado Airborne Multi-Phase Cloud Study (CAMPS) will use the Wyoming King Air research aircraft instrumented with both remote (cloud radar and cloud lidar) and in situ sensors (cloud and particle probes, total water hygrometer) to elucidate the vertical and horizontal structure of cold mixed-phase clouds.
Intellectual Merit:
The data gathered during CAMPS will include information about macro- and microphysical parameters of mixed-phase clouds obtained by both in situ and remote-sensing methods. These data will be analyzed to address a number of important questions about the structure, properties and impacts of mixed-phase clouds. Specific goals include:
1. To assess the vertical and horizontal structure and spatial and temporal variation of cloud properties (particle size distribution, ice and liquid water content, particle habit) in liquid, mixed-phase and precipitating clouds at a mid-latitude continental site with complex terrain during winter.
2. To assess the impact of topography and associated variations in vertical forcing on cloud generation and cloud properties.
3. To develop a data set that provides the information necessary for improving the representation of mixed-phase clouds in cloud-resolving and climate models.
4. To provide correlative data for validation of the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program mobile facility and the National Aeronautics and Space Administration A-Train satellite-borne remote sensors.
5. To provide observational confirmation of the redistribution of snowfall associated with riming inhibition due to enhanced CCN.
Broader Impacts:
Ultimately, by enhancing the community's understanding of cloud-scale processes, the data from CAMPS will be the basis for improvements in the representation of clouds in global climate models. This will lead to more accurate calculations of current and future climate. In addition the CAMPS project will contribute to both formal and informal education at a number of levels. At least one graduate student from each of the participating universities will be involved with the field work and/or data analysis related to this project. The investigators will include undergraduates from their institutions in flight-planning and/or meteorology exercises related to CAMPS when possible. Formal educational opportunities for elementary school students will be coordinated by the Storm Peak Laboratory staff, including visits to the laboratory and aircraft and classroom exercises. Outreach activities will include signage at the Steamboat Springs Ski Resort, an interactive display at the gondola building and coordination with the 2011 Steamboat Weather Summit.
This is a collaborative research with researchers from the University of Colorado and the Desert Research Institute to better understand multi-phase clouds over northern Colorado, where these clouds play an important role in wintertime precipitation. The observation platform is University of Wyoming King Air (UWKA), which was equipped with Colorado Laser Hygrometer (CLH), Wyoming Cloud Lidar (WCL) and Wyoming Cloud Radar (WCR), and other in situ probes providing atmospheric state variables as well as cloud microphysical properties. The overall goal of UW part of the project is to use in situ data, especially CLH, to evaluate and improve the ice microphysical property retrievals by combining WCL and WCR and to support other team members to more effectively use WCL and WCR data for their research. Approaches were developed to correct the shattering effect on traditional FSSP measurements, which allow us to have reliable liquid-phase measurements within mixed-phase clouds. The developed approaches can also be applied to long-time historical FSSP measurements within mixed-phase clouds. CLH provided reliable total condense water (TWC) measurements during CAMPS as evaluated with adiabatic liquid water content (LWC) profiles in pure liquid clouds. WCR and WCL measurements are widely used to provide cloud vertical structure and to combine with in situ data for cloud microphysical and dynamical studies. During CAMPS, a ground-based lidar-radar algorithm was adapted and improved for combined WCR and WCL measurements to retrieve ice water content (IWC) and particle effective size profiles. The WCR-WCL ice retrieval algorithm was applied for both pure ice clouds or precipitating ice from stratiform mixed-phase clouds during CAMPS. WCL-WCR retrieved near aircraft IWC were compared with CLH IWC measurements. The comparison results show that the retrieved IWC is about 15% lower than CLH measurements, but 80% of retrieved data are within CLH uncertainty range (15 mg/m3). These results suggest that combined WCL-WCR measurements can provide reliable IWC profiles, which enhances our future cloud profiling capabilities from UWKA or NSF/NCAR C-130. Collocated WCR and WCL data were provided to other groups to better understand cloud and precipitation structures and their integrations with dynamics in the region.
