Journal of Applied Meteorology and Climatology 

About: Journal of Applied Meteorology and Climatology is an academic journal published by American Meteorological Society. The journal publishes majorly in the area(s): Precipitation & Radar. It has an ISSN identifier of 1558-8424. Over the lifetime, 3123 publications have been published receiving 136378 citations. The journal is also known as: JAMC.

Bulk Parameterization of the Snow Field in a Cloud Model

Abstract: A two-dimensional, time-dependent cloud model has been used to simulate a moderate intensity thunderstorm for the High Plains region. Six forms of water substance (water vapor, cloud water, cloud ice, rain, snow and hail, i.e., graupel) are simulated. The model utilizes the “bulk water” microphysical parameterization technique to represent the precipitation fields which are all assumed to follow exponential size distribution functions. Autoconversion concepts are used to parameterize the collision-coalescence and collision-aggregation processes. Accretion processes involving the various forms of liquid and solid hydrometeors are simulated in this model. The transformation of cloud ice to snow through autoconversion (aggregation) and Bergeron process and subsequent accretional growth or aggregation to form hail are simulated. Hail is also produced by various contact mechanisms and via probabilistic freezing of raindrops. Evaporation (sublimation) is considered for all precipitation particles outsi...

On the Average Value of Correlated Time Series, with Applications in Dendroclimatology and Hydrometeorology

Abstract: In a number of areas of applied climatology, time series are either averaged to enhance a common underlying signal or combined to produce area averages. How well, then, does the average of a finite number (N) of time series represent the population average, and how well will a subset of series represent the N-series average? We have answered these questions by deriving formulas for 1) the correlation coefficient between the average of N time series and the average of n such series (where n is an arbitrary subset of N) and 2) the correlation between the N-series average and the population. We refer to these mean correlations as the subsample signal strength (SSS) and the expressed population signal (EPS). They may be expressed in terms of the mean inter-series correlation coefficient r as SSS ≡ (Rn,N)2 ≈ n(1 + (N − 1)r)/ N(1 + (N − 1)r), EPS ≡ RN)2 ≈ Nr/1 + (N − 1)r.Similar formulas are given relating these mean correlations to the fractional common variance which arises as a parameter in a...

The Palmer Drought Severity Index: Limitations and Assumptions

Abstract: The structure of the Palmer Drought Severity Index (PDSI), which is perhaps the most widely used regional index of drought, is examined. The PDSI addresses two of the most elusive properties of droughts: their intensity and their beginning and ending times. Unfortunately, the index uses rather arbitrary rules in quantifying these properties. In addition, the methodology used to standardize the values of the PDSI for different locations and months is based on very limited comparisons and is only weakly justified on physical or statistical grounds. Under certain conditions, the PDSI values are very sensitive to the criteria for ending an “established” drought and precipitation during a month can have a very large effect on the PDSI values for several previous months. The distribution of the PDSI conditioned on the value for the previous month may often be bimodal. Thus, conventional time series models may be quite limited in their ability to capture the stochastic properties of the index.

Global Vegetation and Land Use: New High-Resolution Data Bases for Climate Studies

Abstract: Global vegetation and land-use data bases (1° latitude by 1° longitude resolution), designed for use in studies of climate and climate change, were compiled in digital form drawing upon approximately 100 published sources complemented by a large collection of satellite imagery. The vegetation data were encoded using the UNESCO classification system; land-use data were encoded using a classification system developed by the author. The vegetation and land-use data were then integrated into a land-cover data base. Areal estimates for most ecosystems from the land-cover data base were found to be significantly different from areal estimates derived from two other global land-cover sources. Possible explanations for discrepancies among these data bases include differences in ecosystem definitions and source material used in compilation. From areal estimates of major ecosystems, derived from the new vegetation and land-cover data bases it is estimated that the total ecosystem reduction caused by agricu...

Simple Solar Spectral Model for Direct and Diffuse Irradiance on Horizontal and Tilted Planes at the Earth's Surface for Cloudless Atmospheres

Abstract: In a previous work, we described a simple model for calculating direct normal and diffuse horizontal spectral solar irradiance for cloudless sky conditions. In this paper, we present a new simple model (SPCTRAL2) that incorporates improvements to the simple model approach and an algorithm for calculating spectral irradiance on tilted surfaces. The model was developed using comparisons with rigorous radiative transfer codes and limited outdoor measurements. SPCTRAL2 produces terrestrial spectra between 0.3 and 4.0 μm with a resolution of approximately 10 nm. Inputs to the model include the solar zenith angle, the collector tilt angle, atmospheric turbidity, the amount of precipitable water vapor and ozone, surface pressure, and ground albedo. A major goal of this work is to provide researchers with the capability to calculate spectral irradiance for different atmospheric conditions and different solar collector geometries using microcomputers.