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Weather reconnaissance is the acquisition of weather data used for research and planning. Typically the term reconnaissance refers to observing weather from the air, as opposed to the ground.
Helicopters are not built to withstand the severe turbulence encountered in hurricane rainbands and eye walls. One reason is that a helicopter receives all of its lift from its rotating blades, and they are most likely to break off in hurricane conditions. [1]
The Lockheed C-130 Hercules is used as a weather reconnaissance aircraft, with 5 different versions being used. The current version is the Lockheed C-130J.
The Lockheed WC-130J aircraft is a venerable aircraft for weather reconnaissance. It flies directly into the hurricane, typically penetrating the hurricane's eye several times per mission at altitudes between 500 feet (150 m) and 10,000 feet (3,000 m). The 53rd WRS Hurricane Hunters operate ten WC-130J aircraft for weather reconnaissance.
The WP-3D Orion aircraft flown by the NOAA Hurricane Hunters are heavily instrumented flying laboratories specifically modified to take atmospheric and radar measurements within tropical cyclones and winter storms.
The NOAA Gulfstream IV high altitude jet conducts hurricane surveillance flying upwards of 4,000 miles (6,400 km) each flight to document upper and lower level winds that affect the movement of tropical cyclones. The hurricane models (computer models predicting hurricane tracks and intensity) mainly utilize NOAA G-IV dropwindsonde data that is collected both day and night in storms affecting the United States.
Other aircraft have been used to investigate hurricanes, including an instrumented Lockheed U-2 that was flown in Hurricane Ginny during the 1963 Atlantic hurricane season.
Past aircraft used were the A-20 Havoc, 1944; B-24, 1944–1945; B-17, 1945–1947; B-25, 1946–1947; B-29, 1946–1947. WB-29, 1951–1956; WB-50, 1956–1963; WB-47, 1963–1969; WC-121N 1954-1973; WC-130A,B,E,H, 1965-2005.
Watercraft deployed for use as weather ships have fallen out of favor due to their high operating cost. Unmanned weather buoys replaced weather ships when they became prohibitively expensive. [2] Since the 1970s, their role has been largely superseded by weather buoys by design. [3] Across the northern Atlantic, the number of weather ships dwindled over the years. The original nine ships in the region had fallen to eight by the 1970s. In 1974, the Coast Guard announced plans to terminate the United States stations, and, in 1977, the last United States weather ship was replaced by a newly developed weather buoy. [4]
By 1983, data was still being collected by ships "M" ("Mike"), "R" ("Romeo"), "C" ("Charlie"), and L ("Lima"), [5] Because of high operating costs and budget issues, weather ship "R" was recalled from the Bay of Biscay before the deployment of a weather buoy for the region. This recall was blamed for the minimal warning given in advance of the Great Storm of 1987. [6] The last weather ship was Polarfront, known as weather station "M" at 66°N, 02°E, run by the Norwegian Meteorological Institute. Polarfront' was put out of operation 1 January 2010. Despite the loss of designated weather ships, weather observations from ships continue from a fleet of voluntary merchant vessels in routine commercial operation, which have increased in number over the decades.
Images from satellites provided a resource for forecasting weather for NASA Space Shuttle launches and landings. Meteorologists analyze images to predict regions of cloud formation and dissipation. Special attention is paid to low clouds and convective cloud particularly cumulonimbus incus clouds. Satellite imagery is used to ascertain cloud-top temperatures to analyze the potential for lightning. Certain types of imagery are valued for their ability to view fog and low clouds at night. Satellite imagery in the long term can help enhance the shuttle flight landing procedure. [7]
Prior to shuttle launches or landings, pilots fly aircraft that provide cloud, wind, turbulence, visibility, and precipitation information. Aircraft are flown along the future flight path of the shuttle and observations are noted. This complements radar and satellite data and only provides information that is useful for short-term (up to four hours before launch or landing) but not long-term forecasting. Aerial reconnaissance often provides a more accurate assessment of weather conditions than radar or satellite imagery. [7]
Weather reconnaissance is also provided by weather balloons. [7]
The National Hurricane Center (NHC) is the division of the United States' NOAA/National Weather Service responsible for tracking and predicting tropical weather systems between the Prime Meridian and the 140th meridian west poleward to the 30th parallel north in the northeast Pacific Ocean and the 31st parallel north in the northern Atlantic Ocean. The agency, which is co-located with the Miami branch of the National Weather Service, is situated on the campus of Florida International University in University Park, Miami, Florida.
A weather satellite or meteorological satellite is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be polar orbiting, or geostationary.
The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of the National Oceanic and Atmospheric Administration (NOAA) branch of the Department of Commerce, and is headquartered in Silver Spring, Maryland, within the Washington metropolitan area. The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970.
The Lockheed WP-3D Orion is a highly modified P-3 Orion used by the Aircraft Operations Center division of the National Oceanic and Atmospheric Administration (NOAA). Only two of these aircraft exist, each incorporating numerous features for the role of collecting weather information. During the Atlantic hurricane season, the WP-3Ds are deployed for duty as hurricane hunters. The aircraft also support research on other topics, such as Arctic ice coverage, air chemistry studies, and ocean water temperature and current analysis.
The Lockheed WC-130 is a high-wing, medium-range aircraft used for weather reconnaissance missions by the United States Air Force. The aircraft is a modified version of the C-130 Hercules transport configured with specialized weather instrumentation including a dropsonde deployment/receiver system and crewed by a meteorologist for penetration of tropical cyclones and winter storms to obtain data on movement, size and intensity.
Hurricane hunters, typhoon hunters, or cyclone hunters are aircrews that fly into tropical cyclones to gather weather data. In the United States, the organizations that fly these missions are the United States Air Force Reserve's 53rd Weather Reconnaissance Squadron and the National Oceanic and Atmospheric Administration's Hurricane Hunters. Such missions have also been flown by Navy units and other Air Force and NOAA units. Other organizations also fly these missions, such as Government Flying Service Hong Kong.
The 53rd Weather Reconnaissance Squadron, also known by its nickname, Hurricane Hunters, is a flying unit of the United States Air Force, and "the only Department of Defense organization still flying into tropical storms and hurricanes." Aligned under the 403rd Wing of the Air Force Reserve Command (AFRC) and based at Keesler Air Force Base, Mississippi, with ten aircraft, it flies into tropical cyclones in the Atlantic Ocean, the Caribbean Sea, the Gulf of Mexico and the Central Pacific Ocean for the specific purpose of directly measuring weather data in and around those storms. The 53rd WRS currently operates the Lockheed WC-130J aircraft as its weather data collection platform.
A dropsonde is an expendable weather reconnaissance device created by the National Center for Atmospheric Research (NCAR), designed to be dropped from an aircraft at altitude over water to measure storm conditions as the device falls to the surface. The sonde contains a GPS receiver, along with pressure, temperature, and humidity (PTH) sensors to capture atmospheric profiles and thermodynamic data. It typically relays this data to a computer in the aircraft by radio transmission.
An annular tropical cyclone is a tropical cyclone that features a normal to large, symmetric eye surrounded by a thick and uniform ring of intense convection, often having a relative lack of discrete rainbands, and bearing a symmetric appearance in general. As a result, the appearance of an annular tropical cyclone can be referred to as akin to a tire or doughnut. Annular characteristics can be attained as tropical cyclones intensify; however, outside the processes that drive the transition from asymmetric systems to annular systems and the abnormal resistance to negative environmental factors found in storms with annular features, annular tropical cyclones behave similarly to asymmetric storms. Most research related to annular tropical cyclones is limited to satellite imagery and aircraft reconnaissance as the conditions thought to give rise to annular characteristics normally occur over open water, well removed from landmasses where surface observations are possible.
A tropical cyclone forecast model is a computer program that uses meteorological data to forecast aspects of the future state of tropical cyclones. There are three types of models: statistical, dynamical, or combined statistical-dynamic. Dynamical models utilize powerful supercomputers with sophisticated mathematical modeling software and meteorological data to calculate future weather conditions. Statistical models forecast the evolution of a tropical cyclone in a simpler manner, by extrapolating from historical datasets, and thus can be run quickly on platforms such as personal computers. Statistical-dynamical models use aspects of both types of forecasting. Four primary types of forecasts exist for tropical cyclones: track, intensity, storm surge, and rainfall. Dynamical models were not developed until the 1970s and the 1980s, with earlier efforts focused on the storm surge problem.
The Dvorak technique is a widely used system to estimate tropical cyclone intensity based solely on visible and infrared satellite images. Within the Dvorak satellite strength estimate for tropical cyclones, there are several visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity. The primary patterns used are curved band pattern (T1.0-T4.5), shear pattern (T1.5–T3.5), central dense overcast (CDO) pattern (T2.5–T5.0), central cold cover (CCC) pattern, banding eye pattern (T4.0–T4.5), and eye pattern (T4.5–T8.0).
The Atlantic hurricane reanalysis project of the National Oceanic and Atmospheric Administration seeks to correct and add new information about past North Atlantic hurricanes. It was started around 2000 to update HURDAT, the official hurricane database for the Atlantic Basin, which has become outdated since its creation due to various systematic errors introduced into the database over time. This effort has involved reanalyses of ship observations from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) as well as reanalyses done by other researchers over the years. It has been ongoing as of 2016.
Tropical cyclone observation has been carried out over the past couple of centuries in various ways. The passage of typhoons, hurricanes, as well as other tropical cyclones have been detected by word of mouth from sailors recently coming to port or by radio transmissions from ships at sea, from sediment deposits in near shore estuaries, to the wiping out of cities near the coastline. Since World War II, advances in technology have included using planes to survey the ocean basins, satellites to monitor the world's oceans from outer space using a variety of methods, radars to monitor their progress near the coastline, and recently the introduction of unmanned aerial vehicles to penetrate storms. Recent studies have concentrated on studying hurricane impacts lying within rocks or near shore lake sediments, which are branches of a new field known as paleotempestology. This article details the various methods employed in the creation of the hurricane database, as well as reconstructions necessary for reanalysis of past storms used in projects such as the Atlantic hurricane reanalysis.
Tropical cyclone forecasting is the science of forecasting where a tropical cyclone's center, and its effects, are expected to be at some point in the future. There are several elements to tropical cyclone forecasting: track forecasting, intensity forecasting, rainfall forecasting, storm surge, tornado, and seasonal forecasting. While skill is increasing in regard to track forecasting, intensity forecasting skill remains unchanged over the past several years. Seasonal forecasting began in the 1980s in the Atlantic basin and has spread into other basins in the years since.
Tropical cyclone track forecasting involves predicting where a tropical cyclone is going to track over the next five days, every 6 to 12 hours. The history of tropical cyclone track forecasting has evolved from a single-station approach to a comprehensive approach which uses a variety of meteorological tools and methods to make predictions. The weather of a particular location can show signs of the approaching tropical cyclone, such as increasing swell, increasing cloudiness, falling barometric pressure, increasing tides, squalls and heavy rainfall.
The Hurricane Weather Research and Forecasting (HWRF) model is a specialized version of the weather research and forecasting model and is used to forecast the track and intensity of tropical cyclones. The model was developed by the National Oceanic and Atmospheric Administration (NOAA), the U.S. Naval Research Laboratory, the University of Rhode Island, and Florida State University. It became operational in 2007.
The maximum sustained wind associated with a tropical cyclone is a common indicator of the intensity of the storm. Within a mature tropical cyclone, it is found within the eyewall at a distance defined as the radius of maximum wind, or RMW. Unlike gusts, the value of these winds are determined via their sampling and averaging the sampled results over a period of time. Wind measuring has been standardized globally to reflect the winds at 10 metres (33 ft) above mean sea level, and the maximum sustained wind represents the highest average wind over either a one-minute (US) or ten-minute time span, anywhere within the tropical cyclone. Surface winds are highly variable due to friction between the atmosphere and the Earth's surface, as well as near hills and mountains over land.
Hurricane Ava was the earliest forming Category 5 hurricane on record in the East Pacific basin. The storm is also tied with 2006's Hurricane Ioke as the fifth-strongest Pacific hurricane on record. It was the first named storm of the 1973 Pacific hurricane season. Forming in early June, Hurricane Ava eventually reached Category 5 intensity on the Saffir–Simpson hurricane scale, the first Pacific hurricane to do so in June and the earliest ever in a season. Its central pressure made it the most intense known Pacific hurricane at the time. Despite its intensity, Ava stayed at sea without significant impact.
The NOAA Hurricane Hunters are a group of aircraft used for hurricane reconnaissance by the United States National Oceanic and Atmospheric Administration (NOAA). They fly through hurricanes to help forecasters and scientists gather operational and research data. The crews also conduct other research projects including ocean wind studies, winter storm research, thunderstorm research, coastal erosion, and air chemistry flights.
The history of Atlantic tropical cyclone warnings details the progress of tropical cyclone warnings in the North Atlantic Ocean. The first service was set up in the 1870s from Cuba with the work of Father Benito Viñes. After his death, hurricane warning services were assumed by the US Army Signal Corps and United States Weather Bureau over the next few decades, first based in Jamaica and Cuba before shifting to Washington, D.C. The central office in Washington, which would evolve into the National Meteorological Center and the Weather Prediction Center, assumed the responsibilities by the early 20th century. This responsibility passed to regional hurricane offices in 1935, and the concept of the Atlantic hurricane season was established to keep a vigilant lookout for tropical cyclones during certain times of the year. Hurricane advisories issued every 12 hours by the regional hurricane offices began at this time.