Civil Rights
Movements, leaders, victories and the continuing fight for equality.
Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
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In 1968 Shirley Chisholm became the first Black woman elected to the United States Congress. In 1972 she launched a campaign for the Democratic presidential nomination, breaking another political barrier.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
Artist conception of the TRMM satellite | |
| Mission type | Environmental research |
|---|---|
| Operator | NASA |
| COSPAR ID | 1997-074A |
| SATCAT no. | 25063 |
| Mission duration | 18 years |
| Spacecraft properties | |
| Launch mass | 3524 kg |
| Dry mass | 2634 kg[1] |
| Power | 1100 watts |
| Start of mission | |
| Launch date | 27 November 1997, 21:27 UTC |
| Rocket | H-II |
| Launch site | Tanegashima, LA-Y1 |
| Contractor | Mitsubishi Heavy Industries |
| End of mission | |
| Disposal | Deorbited |
| Deactivated | 15 April 2015 |
| Decay date | 16 June 2015, 06:54 UTC[2] |
| Orbital parameters | |
| Reference system | Geocentric orbit[2] |
| Regime | Low Earth orbit |
| Perigee altitude | 366 km (227 mi) |
| Apogee altitude | 381 km (237 mi) |
| Inclination | 35.0° |
| Period | 92.0 minutes |
Programme NASA Earth Probe | |
The Tropical Rainfall Measuring Mission (TRMM) was a joint space mission between NASA and JAXA designed to monitor and study tropical rainfall. The term refers to both the mission itself and the satellite that the mission used to collect data. TRMM was part of NASA's Mission to Planet Earth, a long-term, coordinated research effort to study the Earth as a global system. The satellite was launched on 27 November 1997 from the Tanegashima Space Center in Tanegashima, Japan. TRMM operated for 17 years, including several mission extensions, before being decommissioned on 15 April 2015. TRMM re-entered Earth's atmosphere on 16 June 2015.
Tropical precipitation is a difficult parameter to measure, due to large spatial and temporal variations. However, understanding tropical precipitation is important for weather and climate prediction, as this precipitation contains three-fourths of the energy that drives atmospheric wind circulation.[3] Prior to TRMM, the distribution of rainfall worldwide was known to only a 50% of certainty.[4]
The concept for TRMM was first proposed in 1984. The science objectives, as first proposed, were:[3]
Japan joined the initial study for the TRMM mission in 1986.[3] Development of the satellite became a joint project between the space agencies of the United States and Japan, with Japan providing the Precipitation Radar (PR) and H-II launch vehicle, and the United States providing the satellite bus and remaining instruments.[5] The project received formal support from the United States Congress in 1991, followed by spacecraft construction from 1993 through 1997. TRMM launched from Tanegashima Space Center on 27 November 1997.[3]
The Tropical Rainfall Measuring Mission (TRMM), one of the spacecraft in the NASA Earth Probe series of research satellites, is a highly focused, limited-objective program aimed at measuring monthly and seasonal rainfall over the global tropics and subtropics. TRMM is a joint project between the United States and Japan to measure rainfall between 35.0° North and 35.0° South at 350 km altitude.[6]
To extend TRMM's mission life beyond its primary mission, NASA boosted the spacecraft's orbit altitude to 402.5 km in 2001.[7]
In 2005, NASA director Michael Griffin decided to extend the mission again by using the propellant originally intended for a controlled descent. This came after a 2002 NASA risk review put the probability of a human injury or death caused by TRMM's uncontrolled re-entry at 1-in-5,000, about twice the casualty risk deemed acceptable for re-entering NASA satellites; and a subsequent recommendation from the National Research Council panel that the mission be extended despite the risk of an uncontrolled entry.[8]
Battery issues began to limit the spacecraft in 2014 and the mission operations team had to make decisions about how to ration power. In March 2014, the VIRS instruments was turned off to extend the battery life.[7]
In July 2014, with propellant on TRMM running low, NASA decided to cease station-keeping maneuvers and allow the spacecraft's orbit to slowly decay, while continuing to collect data. The remaining fuel, initially reserved to avoid collisions with other satellites or space debris, was depleted in early March 2015.[7] Re-entry was originally expected sometime between May 2016 and November 2017, but occurred sooner due to heightened solar activity.[9] The probe's primary sensor, the precipitation radar, was switched off for the final time on 1 April 2015 and the final scientific sensor, LIS, was turned off on 15 April 2015.[8] Re-entry occurred on 16 June 2015 at 06:54 UTC.[10]
The Precipitation Radar (PR) was the first space-borne instrument designed to provide three-dimensional maps of storm structure. The measurements yielded information on the intensity and distribution of the rain, on the rain type, on the storm depth and on the height at which the snow melts into rain. The estimates of the heat released into the atmosphere at different heights based on these measurements can be used to improve models of the global atmospheric circulation. The PR operated at 13.8 GHz and measured the 3-D rainfall distribution over land and ocean surfaces. It defined a layer depth of perception and hence measured rainfall that actually reached the latent heat of atmosphere. It had a 4.3 km resolution at radii with 220 km swath.
The TRMM Microwave Imager (TMI) was a passive microwave sensor designed to provide quantitative rainfall information over a wide swath under the TRMM satellite. By carefully measuring the minute amounts of microwave energy emitted by the Earth and its atmosphere, TMI was able to quantify the water vapor, the cloud water, and the rainfall intensity in the atmosphere. It was a relatively small instrument that consumed little power. This, combined with the wide swath and the quantitative information regarding rainfall made TMI the "workhorse" of the rain-measuring package on Tropical Rainfall Measuring Mission. TMI is not a new instrument. It is based on the design of the highly successful Special Sensor Microwave/Imager (SSM/I) which has been flying continuously on Defense Meteorological Satellites since 1987. The TMI measures the intensity of radiation at five separate frequencies: 10.7, 19.4, 21.3, 37.0, 85.5 GHz. These frequencies are similar to those of the SSM/I, except that TMI has the additional 10.7 GHz channel designed to provide a more-linear response for the high rainfall rates common in tropical rainfall. The other main improvement that is expected from TMI is due to the improved ground resolution. This improvement, however, is not the result of any instrument improvements, but rather a function of the lower altitude of TRMM 402 kilometers compared to 860 kilometers of SSM/I). TMI has a 878-kilometer wide swath on the surface. The higher resolution of TMI on TRMM, as well as the additional 10.7 GHz frequency, makes TMI a better instrument than its predecessors. The additional information supplied by the Precipitation Radar further helps to improve algorithms. The improved rainfall products over a wide swath will serve both TRMM as well as the continuing measurements being made by the SSM/I and radiometers flying on the NASA's EOS-PM (Aqua (satellite)) and the Japanese ADEOS II satellites.
The Visible and Infrared Scanner (VIRS) was one of the three instruments in the rain-measuring package and serves as a very indirect indicator of rainfall. VIRS, as its name implies, sensed radiation coming up from the Earth in five spectral regions, ranging from visible to infrared, or 0.63 to 12 mm. VIRS was included in the primary instrument package for two reasons. First was its ability to delineate rainfall. The second, and even more important reason, was to serve as a transfer standard to other measurements that are made routinely using Polar Operational Environmental Satellites (POES) and Geostationary Operational Environmental Satellite (GOES) satellites. The intensity of the radiation in the various spectral regions (or bands) can be used to determine the brightness (visible and near infrared) or temperature (infrared) of the source.
Clouds and the Earth's Radiant Energy System (CERES) measured the energy at the top of the atmosphere, as well as estimates energy levels within the atmosphere and at the Earth's surface. The CERES instrument was based on the successful Earth Radiation Budget Experiment (ERBS) which used three satellites to provide global energy budget measurements from 1984 to 1993.[11] Using information from very high resolution cloud imaging instruments on the same spacecraft, CERES determines cloud properties, including cloud-amount, altitude, thickness, and the size of the cloud particles. These measurements are important to understanding the Earth's total climate system and improving climate prediction models.
It only operated during January–August 1998, and in March 2000, so the available data record is quite brief (although later CERES instruments were flown on other missions such as the Earth Observing System (EOS) AM (Terra) and PM (Aqua) satellites.)
The Lightning Imaging Sensor (LIS) was a small, highly sophisticated instrument that detects and locates lightning over the tropical region of the globe. The lightning detector was a compact combination of optical and electronic elements including a staring imager capable of locating and detecting lightning within individual storms. The imager's field of view allowed the sensor to observe a point on the Earth or a cloud for 80 seconds, a sufficient time to estimate the flashing rate, which told researchers whether a storm was growing or decaying.
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The Tropical Rainfall Measuring Mission (TRMM) was a joint space mission between NASA and JAXA designed to monitor and study tropical rainfall. The term refers to both the mission itself and the satellite that the mission used to collect data. TRMM was part of NASA's Mission to Planet Earth, a long-term, coordinated research effort to study the Earth as a global system. The satellite was launched on 27 November 1997 from the Tanegashima Space Center in Tanegashima, Japan. TRMM operated for 17 years, including several mission extensions, before being decommissioned on 15 April 2015. TRMM re-entered Earth's atmosphere on 16 June 2015.
The characteristics of United States rainfall climatology differ significantly across the United States and those under United States sovereignty. Summer and early fall bring brief, but frequent thundershowers and tropical cyclones which create a wet summer and drier winter in the eastern Gulf and lower East Coast. During the winter and spring, Pacific storm systems bring Hawaii and the western United States most of their precipitation. Low pressure systems moving up the East Coast and through the Great Lakes, bring cold season precipitation to from the Midwest to New England, as well as Great Salt Lake. The snow to liquid ratio across the contiguous United States averages 13:1, meaning 13 inches (0.33 m) of snow melts down to 1 inch (25 mm) of water. During the summer, the North American monsoon combined with Gulf of California and Gulf of Mexico moisture moving around the subtropical ridge in the Atlantic Ocean bring the promise of afternoon and evening air-mass thunderstorms to the southern tier of the country as well as the Great Plains. Equatorward of the subtropical ridge, tropical cyclones enhance precipitation across southern and eastern sections of the country, as well as Puerto Rico, the United States Virgin Islands, the Northern Mariana Islands, Guam, and American Samoa. Over the top of the ridge, the jet stream brings a summer precipitation maximum to the Great Plains and western Great Lakes. Large thunderstorm areas known as mesoscale convective complexes move through the Plains, Midwest, and Great Lakes during the warm season, contributing up to 10% of the annual precipitation to the region. The El Niño–Southern Oscillation affects the precipitation distribution, by altering rainfall patterns across the West, Midwest, the Southeast, and throughout the tropics. There is also evidence that global warming is leading to increased precipitation to the eastern portions of North America, while droughts are becoming more frequent in the western portions. Furthermore, global La Niña meteorological events are generally associated with drier and hotter conditions and further exacerbation of droughts in California and the Southwestern and to some extent the Southeastern United States. Meteorological scientists have observed that La Niñas have become more frequent over time.
Tropical cyclone rainfall forecasting involves using scientific models and other tools to predict the precipitation expected in tropical cyclones such as hurricanes and typhoons. Knowledge of tropical cyclone rainfall climatology is helpful in the determination of a tropical cyclone rainfall forecast. More rainfall falls in advance of the center of the cyclone than in its wake. The heaviest rainfall falls within its central dense overcast and eyewall. Slow moving tropical cyclones, like Hurricane Danny and Hurricane Wilma, can lead to the highest rainfall amounts due to prolonged heavy rains over a specific location. However, vertical wind shear leads to decreased rainfall amounts, as rainfall is favored downshear and slightly left of the center and the upshear side is left devoid of rainfall. The presence of hills or mountains near the coast, as is the case across much of Mexico, Haiti, the Dominican Republic, much of Central America, Madagascar, Réunion, China, and Japan act to magnify amounts on their windward side due to forced ascent causing heavy rainfall in the mountains. A strong system moving through the mid latitudes, such as a cold front, can lead to high amounts from tropical systems, occurring well in advance of its center. Movement of a tropical cyclone over cool water will also limit its rainfall potential. A combination of factors can lead to exceptionally high rainfall amounts, as was seen during Hurricane Mitch in Central America. Use of forecast models can help determine the magnitude and pattern of the rainfall expected. Climatology and persistence models, such as r-CLIPER, can create a baseline for tropical cyclone rainfall forecast skill. Simplified forecast models, such as the Kraft technique and the eight and sixteen-inch rules, can create quick and simple rainfall forecasts, but come with a variety of assumptions which may not be true, such as assuming average forward motion, average storm size, and a knowledge of the rainfall observing network the tropical cyclone is moving towards. The forecast method of TRaP assumes that the rainfall structure the tropical cyclone currently has changes little over the next 24 hours. The global forecast model which shows the most skill in forecasting tropical cyclone-related rainfall in the United States is the ECMWF IFS (Integrated Forecasting System).
The state of Karnataka in India experiences diverse rainfall quantities across its regions. While Malnad and Coastal Karnataka receive copious amount of rainfall, its north Bayaluseemae region in the Deccan Plateau is one of the most arid regions in the country. Most of the rains received in the state is during the monsoon season. Being an agrarian economy with a large percentage of its citizens engaged in agriculture, the failure of rains can have a crippling effect on the economy of the state. Apart from the benefits in agriculture, the Government of Karnataka has tried to avail other benefits of rainfall using scientific methods. An example of this is the project, Rainwater Harvesting in Rural Karnataka which is initiated by the Karnataka State Council for Science and Technology and is one of the largest rainwater harvesting projects in the world. Agumbe in the Shimoga district, Amagaon in Belgaum District, Hulikal again in Shimoga district and Talakaveri in Madikeri are some of the known places with the highest annual rainfall in South India. Of this Amagaon has received over 10000 mm rain fall twice in 10 years. Naravi is a village in Belthangady taluk also a highest raining village in karnataka but scientifically not recorded. Agumbe and Hulikal in Shivamogga District of Western Ghat region is considered as "Cheerapunji of South India" but still some places in Western Ghats region had resulted much more rainfall than these two villages. Amagaon in Belgaum District recorded magical number of 10,068mm in the year 2010, Mundrote in Kodagu district recorded 9974mm in the year 2011. The table below compares rainfall between Agumbe in Thirthahalli taluk in Shimoga district, Hulikal in Hosanagara taluk in Shimoga district, Amagaon in Khanapur Taluk in Belgaum district and Talacauvery and Mundrote in Madikeri taluk in Kodagu district, Kokalli of Sirsi Taluk, Nilkund of Siddapur Taluk, CastleRock of Supa (Joida) Taluk in Uttara Kannada District, Kollur in Udupi District to show which one can be called the "Cherrapunji of South India". The following were the top 5 places that recorded highest rainfall in statistics [2010-2017] The following places recorded highest rainfall with respect to each year [2010-2017]
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Joe Louis.