Meteorologists in map room at the U.S. Weather Service

Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].

Oceanographic and meteorological observations for project Little Window: March 1970

ENGLISH: Project Little Window was planned to provide some answers to the important scientific question of whether or not the HRIR (high resolution infrared radiometer) sensors aboard NASA and NOAA satellites can provide useful data for much of the oceanographic community. The sensors aboard these satellites were designed in response to the initial needs of meteorologists for temperature measurements integrated over a distance of 5-10 nautical miles and extending over a range from 30°C to about -75°C (i2-4°C). To this end the sensors have been a very powerful tool to the meteorologist in preparing daily weather advisories and in carrying out research. SPANISH: El proyecto Little Window fue planeado para suministrar algunas respuestas al importante tema científico sobre si los captadores (ltsensors") infrarrojos de alta resoluci6n (IRAR) a bordo de los satélites NASA y NOAA, pueden o no proveer datos útiles para la mayor1a de los oceanógrafos. Los captadores a bordo de estos satélites fueron concebidos en respuesta a las necesidades iniciales de los meteor6logos para obtener mediciones de temperatura integradas sobre una distancia de 5-10 millas náuticas, y entre 30°c y aproximadamente -75°C (~2-4°C). Con este fin los captadores han sido un instrumento poderoso para el meteor6logo en la preparaci6n de las informaciones diarias de tiempo y en la realizaci6n de las investigaciones. (PDF contains 171 pages.)

Multiple-scattering in radar systems: a review

Although extensively studied within the lidar community, the multiple scattering phenomenon has always been considered a rare curiosity by radar meteorologists. Up to few years ago its appearance has only been associated with two- or three-body-scattering features (e.g. hail flares and mirror images) involving highly reflective surfaces. Recent atmospheric research aimed at better understanding of the water cycle and the role played by clouds and precipitation in affecting the Earth's climate has driven the deployment of high frequency radars in space. Examples are the TRMM 13.5 GHz, the CloudSat 94 GHz, the upcoming EarthCARE 94 GHz, and the GPM dual 13-35 GHz radars. These systems are able to detect the vertical distribution of hydrometeors and thus provide crucial feedbacks for radiation and climate studies. The shift towards higher frequencies increases the sensitivity to hydrometeors, improves the spatial resolution and reduces the size and weight of the radar systems. On the other hand, higher frequency radars are affected by stronger extinction, especially in the presence of large precipitating particles (e.g. raindrops or hail particles), which may eventually drive the signal below the minimum detection threshold. In such circumstances the interpretation of the radar equation via the single scattering approximation may be problematic. Errors will be large when the radiation emitted from the radar after interacting more than once with the medium still contributes substantially to the received power. This is the case if the transport mean-free-path becomes comparable with the instrument footprint (determined by the antenna beam-width and the platform altitude). This situation resembles to what has already been experienced in lidar observations, but with a predominance of wide- versus small-angle scattering events. At millimeter wavelengths, hydrometeors diffuse radiation rather isotropically compared to the visible or near infrared region where scattering is predominantly in the forward direction. A complete understanding of radiation transport modeling and data analysis methods under wide-angle multiple scattering conditions is mandatory for a correct interpretation of echoes observed by space-borne millimeter radars. This paper reviews the status of research in this field. Different numerical techniques currently implemented to account for higher order scattering are reviewed and their weaknesses and strengths highlighted. Examples of simulated radar backscattering profiles are provided with particular emphasis given to situations in which the multiple scattering contributions become comparable or overwhelm the single scattering signal. We show evidences of multiple scattering effects from air-borne and from CloudSat observations, i.e. unique signatures which cannot be explained by single scattering theory. Ideas how to identify and tackle the multiple scattering effects are discussed. Finally perspectives and suggestions for future work are outlined. This work represents a reference-guide for studies focused at modeling the radiation transport and at interpreting data from high frequency space-borne radar systems that probe highly opaque scattering media such as thick ice clouds or precipitating clouds.

Review of theories for blocking

A typical feature of the atmospheric circulation at middle and high latitudes is a tendency to fluctuate between two rather extreme circulation patterns. This behaviour of the atmosphere is most common at the Northern Hemisphere during the winter and has been known among the meteorologists for a considerable time (e.g. Garriott (1904)). One of these two states is identified by a predominantly zonal circulation or a so-called high-index circulation, the other state by a meridional or a low-index circulation. The meridional circulation is often broken up in a characteristic atmospheric pattern of cut-off lows and highs. These features usually have a time scale of several days during which they affect the weather in a very dominating way. The transition from the zonal to the meridional or cellular circulation is very characteristic and follows a very typical chain of events.

The catastrophic flash-flood event of 8–9 September 2002 in the Gard region, France: a first case study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory

The Cévennes–Vivarais Mediterranean Hydrometeorological Observatory (OHM-CV) is a research initiative aimed at improving the understanding and modeling of the Mediterranean intense rain events that frequently result in devastating flash floods in southern France. A primary objective is to bring together the skills of meteorologists and hydrologists, modelers and instrumentalists, researchers and practitioners, to cope with these rather unpredictable events. In line with previously published flash-flood monographs, the present paper aims at documenting the 8–9 September 2002 catastrophic event, which resulted in 24 casualties and an economic damage evaluated at 1.2 billion euros (i.e., about 1 billion U.S. dollars) in the Gard region, France. A description of the synoptic meteorological situation is first given and shows that no particular precursor indicated the imminence of such an extreme event. Then, radar and rain gauge analyses are used to assess the magnitude of the rain event, which was particularly remarkable for its spatial extent with rain amounts greater than 200 mm in 24 h over 5500 km2. The maximum values of 600–700 mm observed locally are among the highest daily records in the region. The preliminary results of the postevent hydrological investigation show that the hydrologic response of the upstream watersheds of the Gard and Vidourle Rivers is consistent with the marked space–time structure of the rain event. It is noteworthy that peak specific discharges were very high over most of the affected areas (5–10 m3 s−1 km−2) and reached locally extraordinary values of more than 20 m3 s−1 km−2. A preliminary analysis indicates contrasting hydrological behaviors that seem to be related to geomorphological factors, notably the influence of karst in part of the region. An overview of the ongoing meteorological and hydrological research projects devoted to this case study within the OHM-CV is finally presented.

Visualização científica de descargas elétricas atmosféricas

This paper aims to develop a web application for viewing Atmospheric Electrical Discharge, plotting marks on a map, using as base data provided by SIMEPAR. The developed system uses techniques and tools which enable the creation of Web system without requiring the use of plugins or external software, running on virtually all web browsers and platforms. This tool aims to aid meteorologists monitor agile discharges and help society at large to prevent accidents caused by this phenomenon of nature

Sulla fondazione di una societáa meteorologica per la Lombardia : rapporto-programma approvato dal Reale Istituto lombardo di scienze, lettere ed arti.

Both copies: University of Illinois bookplate: "From the library of Conte Antonio Cavagna Sangiuliani di Gualdana Lazelada di Bereguardo, purchased 1921".

U.S. Army meteorologist Private Merle Coleman at White Sands Missile Range in Las Cruces, New Mexico

General note: Title and date provided by Bettye Lane.

Weather forecaster at work

Inscription: Verso: Laura Cole, weather forecaster, at radar scope, U.S. weather service.

Improving multivariate data streams clustering.

Clustering data streams is an important task in data mining research. Recently, some algorithms have been proposed to cluster data streams as a whole, but just few of them deal with multivariate data streams. Even so, these algorithms merely aggregate the attributes without touching upon the correlation among them. In order to overcome this issue, we propose a new framework to cluster multivariate data streams based on their evolving behavior over time, exploring the correlations among their attributes by computing the fractal dimension. Experimental results with climate data streams show that the clusters' quality and compactness can be improved compared to the competing method, leading to the thoughtfulness that attributes correlations cannot be put aside. In fact, the clusters' compactness are 7 to 25 times better using our method. Our framework also proves to be an useful tool to assist meteorologists in understanding the climate behavior along a period of time.

INTERNET Y LA GEOGRAFÍA

 Los geógrafos ahora tienen a su disposición la red mundial de INTERNET. Esta res es mucho más que un depósito gigante de datos y programas. Es un cúmulo de experiencias humanas que incluyen texto, artículos, imagen,  video y foros de discusión. Es una nueva forma de procesamiento a la información de formas que antes considerábamos imposibles. El profesional que continúe procesando y obteniendo información de la manera tradicional se estará quedando al margen de nuevo conocimiento disponible a diario en INTERNET. El profesional de hoy no se limita a recopilar información en una biblioteca o librería, sino que accesa directamente sitios de búsqueda que le permitirán encontrar rápidamente los datos que busca. Un ejemplo, son los meteorólogos que tienen en INTERNET su mejor herramienta, ya que pueden recuperar imágenes sobre el clima casi inmediatamente después que son almacenadas desde el satélite, lo cual les permite evaluar y discernir sobre el estado actual del clima (Aberdeen University Compiting Center, 1996). Las imágenes las pueden ver y bajar a su computadora individual para su propio uso. Los profesores en la actualidad brindan al estudiante todo su material almacenándolo en INTERNET. La relación profesor-estudiante ya no es la misma. Al estudiante se le exige encontrar la información en su computadora y asimilarla. El viejo cuaderno no es necesario, las lecciones pueden ser recuperadas para su estudio sin que el profesor tenga que impartirlas, como se hace en la mayoría de las universidades de los Estados Unidos (Ohio State University, 1996). En general, este articulo persigue mostrar a los profesionales de las ciencias geográficas, dónde encontrar la información que buscan t cómo localizar más de lo que imaginan con la red INTERNET.  ABSTRACT Geographers now have at their disposition the world network of INTERNET. This network is much more than just a large deposit of digital data and programs. It is an accumulation of human experiences that include text, articles, images, videos, and discussion bulletin boards. It is a new form of processing and managing information that was previously considered impossible. The professional who continues searching and obtaining information by traditional methods will be left on the fringes of this new wave of digital information and material available daily on INTERNET. Hence, a professional is not limited to compiling information in libraries or bookstores as direct and rapid access of desired research materials is available on the INTERNET. For example, meteorologists have in INTERNET their best tool in that they can acquire meteorologic satellite images, which permit them to evaluate and discern the actual present climatic situation (Aberdeen University Computing Center, 1996). One can see and then down load to one´s personal computer imagines of interest for personal use. Professors can offer to students all their materials for a class through and stores on the INTERNET. The relationship between professor and student is not the same. Students can be asked to access and assimilate the information via individual computers connected to the INTERNTET. Notebooks are becoming obsolete given that all class lectures and materials could be placed on the INTERNET for review without a professor having to give a lecture, as is being done in many universities of the United States (Ohio State University, 1996).This article pursues showing, in general, where professionals in Geographical Sciences can find available information and much more on the INTERNET.