2006 Performance Metrics
Each year, the ARM Program must submit to DOE an overall performance measure related to scientific achievement. The overall performance measure includes specific metrics for reporting progress each quarter. This reporting process includes support documentation (usually a report or data file) appropriate for the metric.
Overall Performance Measure
Improve Climate Models
Evaluate the extent of agreement between climate model simulations of water vapor concentration and cloud properties and measurements of these quantities on the timescale of 1-4 days using an initial condition model testbed. Use these evaluations to diagnose parameterization inadequacies and improve them for climate simulations. Produce a new continuous time series of retrieved cloud properties at each ARM site for use in evaluating and improving climate models. This data set will provide the necessary link between cloud properties and the models that are attempting to simulate them.
1st Quarter Metric—Completed
Complete continuous time series of water vapor for selected 30-day periods for each of the fixed ARM sites.
Product Definition/Description – Produce continuous water vapor profiles using a new technique devised to incorporate radiosonde data, microwave radiometer data, and analysis information from numerical weather forecast models. Data from the European Center for Medium Range Weather Forecasts (ECMWF) model will be used as a constraint. These profiles will then be compared with subsequent climate model output.
Product Documentation/Deliverables – The results of this water vapor time series development will be documented in a short report and made available from the ARM website. Data sets will be delivered to the Data Archive no later than 10 days after the end of the quarter.
Result – Data files containing continuous water vapor profiles have been generated for the Southern Great Plains for March 2000, the North Slope of Alaska from 01 March through 15 April 2004, and the Tropical Western Pacific at Darwin for January 2005. The data and documentation are available from the Data Archive PI data products.
2nd Quarter Metric—Completed
Evaluate the extent of agreement between climate models simulations and measurements of water vapor on timescales of 1-4 day periods using an initial condition model testbed.
Product Definition/Description – Comparison between short-range forecasts of the National Center for Atmospheric Research (NCAR) and the Geophysical Fluid Dynamics Laboratory (GFDL) climate models and ARM measurements of water vapor will be performed at each of the fixed ARM sites. The examination periods will be dependent on the availability of ARM data and other data needed for initial forecasts of the climate model. Comparisons will be made in terms of the bias, correlation, and root-mean-square errors of the height profiles and column integrated amounts of water vapor from hours 12 to 36 of the forecasts.
Product Documentation/Deliverables – The results of this comparison will be documented in a short report and made available from the ARM website within 10 days after the end of the quarter.
Result – The model forecast data have successfully been compared to the new merged-sounding
data, which fulfills the second quarter metric. Results show that there is good agreement in these measurements for the Southern Great Plains and North Slope of Alaska and significantly lesser agreement for the Tropical Western Pacific site in Darwin, Australia. To learn more, read A Comparison of Water Vapor Quantities from Model Short-Range Forecasts and ARM Operations.
3rd Quarter Metric—Completed
Produce and refine a 1-year continuous time series of cloud microphysical properties based on cloud radar measurements for each of the fixed ARM sites.
Product Definition/Description – Produce 1-year profiles of cloud microphysical properties using recently-developed algorithms that interpret radar reflectivity profiles, lidar backscatter profiles, and microwave brightness temperatures into the context of the underlying cloud microphysical structure. Because mapping functions used to convert raw information from the remote and passive sensors to geophysically meaningful quantities are typically under-constrained, procedures using assumptions for site location and cloud type have been developed to produce a continuous time series of the microphysical profile. Refinements will be made to the profiles in response to deficiencies uncovered during routine testing through the use of radiative closure experiments.
Product Documentation/Deliverables – The results of this continuous time series of cloud microphysical properties development will be documented in a short report and made available from the ARM website. Data sets will be delivered to the Data Archive no later than 10 days after the end of the quarter.
Result – Vertical profiles of the liquid/ice water content and liquid/ice cloud particle effective radius and cloud fraction at 20-minute intervals and over 230 vertical levels have been produced. Data files have been generated for the Southern Great Plains for March 2000-February 2001, the North Slope of Alaska for January 2004-December 2004, and the Tropical Western Pacific site at Manus Island for November 2003-October 2004. This product is an important step in the calculation of broadband radiative heating rates. The data and documentation are available from the Data Archive PI data products.
4th Quarter Metric—Completed
Evaluate the extent of agreement between climate models simulations and radar-derived measurements of cloud properties on timescales of 1-4 day periods using an initial condition model testbed.
Product Definition/Description – Comparison between short-range forecasts of the NCAR and the GFDL climate models and ARM measurements of cloud properties will be performed at each of the fixed ARM sites. The examination periods will be dependent on the availability of ARM data and other data needed for initial forecasts of the climate models. Comparisons will be made in terms of the bias, correlation, and root-mean-square errors of the height profiles and column integrated amounts of cloud amount, cloud liquid water, and cloud ice water from hours 12 to 36 of the forecasts.
Product Documentation/Deliverables – The results of this comparison will be documented in a short report and made available from the ARM website within 10 days after the end of the quarter.
Result – Model forecast data have been successfully compared to the new ARM microbase data (third quarter result), which fulfills the fourth quarter metric. Results show that there is good agreement in both the time height as well as integrated quantities for the Southern Great Plains and reasonable agreement at the North Slope of Alaska. However, the Tropical Western Pacific site shows significantly lesser agreement for both time height and integrated quantities examined herein. To learn more, read A Comparison of Model Short-Range Forecasts and the ARM Microbase Data.
