Meteorology and Atmospheric Physics 

About: Meteorology and Atmospheric Physics is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Monsoon & Precipitation. It has an ISSN identifier of 0177-7971. Over the lifetime, 2168 publications have been published receiving 54377 citations.

A comprehensive meteorological modeling system?RAMS

Abstract: This paper presents a range of applications of the Regional Atmospheric Modeling System (RAMS), a comprehensive mesoscale meterological modeling system. Applications discussed in this paper include large eddy simulations (LES) and simulations of thunderstorms, cumulus fields, mesoscale convective systems, mid-latitude cirrus clouds, winter storms, mechanically- and thermally-forced mesoscale systems, and mesoscale atmospheric disperision. A summary of current RAMS options is also presented. Improvements to RAMS currently underway include refinements to the cloud radiation, cloud microphysics, cumulus, and surface soil/vegetative parameterization schemes, the parallelization of the code, development of a more versatile visualization capability, and research into meso-α-scale cumulus parameterization.

The East Asian summer monsoon: an overview

Abstract: The present paper provides an overview of major problems of the East Asian summer monsoon. The summer monsoon system over East Asia (including the South China Sea (SCS)) cannot be just thought of as the eastward and northward extension of the Indian monsoon. Numerous studies have well documented that the huge Asian summer monsoon system can be divided into two subsystems: the Indian and the East Asian monsoon system which are to a greater extent independent of each other and, at the same time, interact with each other. In this context, the major findings made in recent two decades are summarized below: (1) The earliest onset of the Asian summer monsoon occurs in most of cases in the central and southern Indochina Peninsula. The onset is preceded by development of a BOB (Bay of Bengal) cyclone, the rapid acceleration of low-level westerlies and significant increase of convective activity in both areal extent and intensity in the tropical East Indian Ocean and the Bay of Bengal. (2) The seasonal march of the East Asian summer monsoon displays a distinct stepwise northward and northeastward advance, with two abrupt northward jumps and three stationary periods. The monsoon rain commences over the region from the Indochina Peninsula-the SCS-Philippines during the period from early May to mid-May, then it extends abruptly to the Yangtze River Basin, and western and southern Japan, and the southwestern Philippine Sea in early to mid-June and finally penetrates to North China, Korea and part of Japan, and the topical western West Pacific. (3) After the onset of the Asian summer monsoon, the moisture transport coming from Indochina Peninsula and the South China Sea plays a crucial “switch” role in moisture supply for precipitation in East Asia, thus leading to a dramatic change in climate regime in East Asia and even more remote areas through teleconnection. (4) The East Asian summer monsoon and related seasonal rain belts assumes significant variability at intraseasonal, interannual and interdecadal time scales. Their interaction, i.e., phase locking and in-phase or out-phase superimposing, can to a greater extent control the behaviors of the East Asian summer monsoon and produce unique rythem and singularities. (5) Two external forcing i.e., Pacific and Indian Ocean SSTs and the snow cover in the Eurasia and the Tibetan Plateau, are believed to be primary contributing factors to the activity of the East Asian summer monsoon. However, the internal variability of the atmospheric circulation is also very important. In particular, the blocking highs in mid-and high latitudes of Eurasian continents and the subtropical high over the western North Pacific play a more important role which is quite different from the condition for the South Asian monsoon. The later is of tropical monsoon nature while the former is of hybrid nature of tropical and subtropical monsoon with intense impact from mid-and high latitudes.

The Advanced Regional Prediction System (ARPS) – A multi-scale nonhydrostatic atmospheric simulation and prediction model. Part I: Model dynamics and verification

Abstract: A completely new nonhydrostatic model system known as the Advanced Regional Prediction System (ARPS) has been developed in recent years at the Center for Analysis and Prediction of Storms (CAPS) at the University of Oklahoma. The ARPS is designed from the beginning to serve as an effective tool for basic and applied research and as a system suitable for explicit prediction of convective storms as well as weather systems at other scales. The ARPS includes its own data ingest, quality control and objective analysis packages, a data assimilation system which includes single-Doppler velocity and thermodynamic retrieval algorithms, the forward prediction component, and a self-contained post-processing, diagnostic and verification package. The forward prediction component of the ARPS is a three-dimensional, nonhydrostatic compressible model formulated in generalized terrain-following coordinates. Minimum approximations are made to the original governing equations. The split-explicit scheme is used to integrate the sound-wave containing equations, which allows the horizontal domain-decomposition strategy to be efficiently implemented for distributed-memory massively parallel computers. The model performs equally well on conventional shared-memory scalar and vector processors. The model employs advanced numerical techniques, including monotonic advection schemes for scalar transport and variance-conserving fourth-order advection for other variables. The model also includes state-of-the-art physics parameterization schemes that are important for explicit prediction of convective storms as well as the prediction of flows at larger scales. Unique to this system are the consistent code styling maintained for the entire model system and thorough internal documentation. Modern software engineering practices are employed to ensure that the system is modular, extensible and easy to use. The system has been undergoing real-time prediction tests at the synoptic through storm scales in the past several years over the continental United States as well as in part of Asia, some of which included retrieved Doppler radar data and hydrometeor types in the initial condition. As the first of a two-part paper series, we describe herein the dynamic and numerical framework of the model, together with the subgrid-scale turbulence and the PBL parameterization. The model dynamic and numerical framework is then verified using idealized and realistic mountain flow cases and an idealized density current. Other physics parameterization schemes will be described in Part II, which is followed by verification against observational data of the coupled soil-vegetation model, surface layer fluxes and the PBL parameterization. Applications of the model to the simulation of an observed supercell storm and to the prediction of a real case are also found in Part II. In the latter case, a long-lasting squall line developed and propagated across the eastern part of the United States following a historical number of tornado outbreak in the state of Arkansas.

Air quality model performance evaluation

Abstract: This paper reviews methods to evaluate the performance of air quality models, which are tools that predict the fate of gases and aerosols upon their release into the atmosphere. Because of the large economic, public health, and environmental impacts often associated with the use of air quality model results, it is important that these models be properly evaluated. A comprehensive model evaluation methodology makes use of scientific assessments of the model technical algorithms, statistical evaluations using field or laboratory data, and operational assessments by users in real-world applications. The focus of the current paper is on the statistical evaluation component. It is important that a statistical model evaluation exercise should start with clear definitions of the evaluation objectives and specification of hypotheses to be tested. A review is given of a set of model evaluation methodologies, including the BOOT and the ASTM evaluation software, Taylor’s nomogram, the figure of merit in space, and the CDF approach. Because there is not a single best performance measure or best evaluation methodology, it is recommended that a suite of different performance measures be applied. Suggestions are given concerning the magnitudes of the performance measures expected of “good” models. For example, a good model should have a relative mean bias less than about 30% and a relative scatter less than about a factor of two. In order to demonstrate some of the air quality model evaluation methodologies, two simple baseline urban dispersion models are evaluated using the Salt Lake City Urban 2000 field data. The importance of assumptions concerning details such as minimum concentration and pairing of data are shown. Typical plots and tables are presented, including determinations of whether the difference in the relative mean bias between the two models is statistically significant at the 95% confidence level.

Rainfall thresholds for the initiation of landslides in central and southern Europe

Abstract: We review rainfall thresholds for the initiation of landslides world wide and propose new empirical rainfall thresholds for the Central European Adriatic Danubian South-Eastern Space (CADSES) area, located in central and southern Europe. One-hundred-twenty-four empirical thresholds linking measurements of the event and the antecedent rainfall conditions to the occurrence of landslides are considered. We then describe a database of 853 rainfall events that resulted or did not result in landslides in the CADSES area. Rainfall and landslide information in the database was obtained from the literature; climate information was obtained from the global climate dataset compiled by the Climate Research Unit of the East Anglia University. We plot the intensity-duration values in logarithmic coordinates, and we establish that with increased rainfall duration the minimum intensity likely to trigger slope failures decreases linearly, in the range of durations from 20 minutes to ∼12 days. Based on this observation, we determine minimum intensity-duration (ID) and normalized-ID thresholds for the initiation of landslides in the CADSES area. Normalization is performed using two climatic indexes, the mean annual precipitation (MAP) and the rainy-day-normal (RDN). Threshold curves are inferred from the available data using a Bayesian statistical technique. Analysing the obtained thresholds we establish that lower average rainfall intensity is required to initiate landslides in an area with a mountain climate, than in an area characterized by a Mediterranean climate. We further suggest that for rainfall periods exceeding ∼12 days landslides are triggered by factors not considered by the ID model. The obtained thresholds can be used in operation landslide warning systems, where more accurate local or regional thresholds are not available.