Krista Gaustad

Retrieving Liquid Wat0er Path and Precipitable Water Vapor From the Atmospheric Radiation Measurement (ARM) Microwave Radiometers

Ground-based two-channel microwave radiometers (MWRs) have been used for over 15 years by the Atmospheric Radiation Measurement (ARM) program to provide observations of downwelling emitted radiance from which precipitable water vapor (PWV) and liquid water path (LWP) - two geophysical parameters critical for many areas of atmospheric research - are retrieved. An algorithm that incorporates output from two advanced retrieval techniques, namely, a physical-iterative approach and a computationally efficient statistical method, has been developed to retrieve these parameters. The forward model used in both methods is the monochromatic radiative transfer model MonoRTM. An important component of this MWR RETrieval (MWRRET) algorithm is the determination of small (< 1 K) offsets that are subtracted from the observed brightness temperatures before the retrievals are performed. Accounting for these offsets removes systematic biases from the observations and/or the model spectroscopy necessary for the retrieval, significantly reducing the systematic biases in the retrieved LWP. The MWRRET algorithm significantly provides more accurate retrievals than the original ARM statistical retrieval, which uses monthly retrieval coefficients. By combining the two retrieval methods with the application of brightness temperature offsets to reduce the spurious LWP bias in clear skies, the MWRRET algorithm significantly provides better retrievals of PWV and LWP from the ARM two-channel MWRs compared to the original ARM product.

A scientific data processing framework for time series NetCDF data

The Atmospheric Radiation Measurement (ARM) Data Integrator (ADI) is a framework designed to streamline the development of scientific algorithms that analyze, and models that use time-series NetCDF data. ADI automates the process of retrieving and preparing data for analysis, provides a modular, flexible framework that simplifies software development, and supports a data integration workflow. Algorithm and model input data, preprocessing, and output data specifications are defined through a graphical interface. ADI includes a library of software modules to support the workflow, and a source code generator that produces C, IDL^(R), and Python(TM) templates to jump start development. While developed for processing climate data, ADI can be applied to any time-series data. This paper discusses the ADI framework, and how ADIs capabilities can decrease the time and cost of implementing scientific algorithms allowing modelers and scientists to focus their efforts on their research rather than preparing and packaging data.

Heterogeneity in Warm‐Season Land‐Atmosphere Coupling Over the U.S. Southern Great Plains

Heterogeneity in warm-season (May-August) land-atmosphere (LA) coupling is quantified with the long-time, multiple-station measurements from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program and the moderate-resolution imaging spectroradiometer (MODIS) satellite remote sensing at the Southern Great Plains (SGP). We examine the coupling strength at 7 additional locations with the same surface type (i.e., pasture/grassland) as the ARM SGP central facility (CF). To simultaneously consider multiple factors and consistently quantify their relative contributions, we apply a multiple linear regression method to correlate the surface evaporative fraction (EF) with near-surface soil moisture (SM) and leaf area index (LAI). The observations show moderate to weak terrestrial segment LA coupling with large heterogeneity across the ARM SGP domain in warm-season. Large spatial variabilities in the contributions from SM and LAI to the EF changes are also found. The coupling heterogeneities appear to be associated with differences in land use, anthropogenic activities, rooting depth, and soil type at different stations. Therefore, the complex LA interactions at the SGP cannot be well represented by those at the CF/E13 based on the metrics applied here. Overall, the LAI exerts more influence on the EF than does the SM due to its overwhelming impacts on the latent heat flux. This study complements previous studies based on measurements only from the CF and has important implications for modeling LA coupling in weather and climate models. The multiple linear regression provides a more comprehensive measure of the integrated impacts on LA coupling from several different factors.

An architecture for consolidating multidimensional time-series data onto a common coordinate grid

Consolidating measurement data for use by data models or in inter-comparison studies frequently requires transforming the data onto a common grid. Standard methods for interpolating multidimensional data are often not appropriate for data with non-homogenous dimensionality, and are hard to implement in a consistent manner for different datastreams. These challenges are increased when dealing with the automated procedures necessary for use with continuous, operational datastreams. In this paper we introduce a method of applying a series of one-dimensional transformations to merge data onto a common grid, examine the challenges of ensuring consistent application of data consolidation methods, present a framework for addressing those challenges, and describe the implementation of such a framework for the Atmospheric Radiation Measurement (ARM) program.

ARM Best Estimate Data (ARMBE) Products for Climate Science for a Sustainable Energy Future (CSSEF)

This data set was created for the Climate Science for a Sustainable Energy Future (CSSEF) model testbed project and is an extension of the hourly average ARMBE dataset to other extended facility sites and to include uncertainty estimates. Uncertainty estimates were needed in order to use uncertainty quantification (UQ) techniques with the data.

Power options for lunar exploration

This paper presents an overview of the types of power systems available for providing power on the moon. Lunar missions of exploration, in situ resource utilization, and colonization will be constrained by availability of adequate power. The length of the lunar night places severe limitations on solar power system designs, because a large portion of the system mass is devoted to energy storage. The selection of the ideal power source hardware will require compatibility with not only the lunar base power requirements and environment, but also with the conversion, storage, and transmission equipment. In addition, further analysis to determine the optimum operating parameters for a given power system should be conducted so that critical technologies can be identified in the early stages of base development. This paper describes the various concepts proposed for providing power on the lunar surface and compares their ranges of applicability. The importance of a systems approach to the integration of these com...

ARM: Gridded (0.25 x 0.25 lat/lon) fractional cloud cover, clear-sky and all-sky shortwave flux over the SGP site.

Gridded (0.25 x 0.25 lat/lon) fractional cloud cover, clear-sky and all-sky shortwave flux over the SGP site.

ARM: Fractional cloud cover, clear-sky and all-sky shortwave flux for each of 25 individual SGP facilities.

Fractional cloud cover, clear-sky and all-sky shortwave flux for each of 25 individual SGP facilities.

ARM: Microwave Radiometer Retrievals (MWRRET) of Cloud Liquid Water and Precipitable Water Vapor

Microwave Radiometer Retrievals (MWRRET) of Cloud Liquid Water and Precipitable Water Vapor

Dark after Chernobyl?: Closing former Soviet power reactors

International pressure to close some of the old nuclear reactors built by the former Soviet Union (FSU) has accelerated in the period since that countrys dissolution. This pressure has been countered, however, by the argument that resulting electricity shortfalls would hasten ongoing social and economic dislocations. Under feasible economic scenarios, this paper identifies which regions would likely experience electricity supply shortfalls, outlines what adjustments in electricity transfers between regions could offset the shortfalls, and estimates the implied costs and schedules of related power plant and transmission construction projects. Costs of closure range from less than US