5,357 research outputs found
Improving the altimetric rain record from Jason-1 & Jason-2
No full textDual-frequency rain-flagging has long been a standard part of altimetric data analysis, both for quality control of the data and for the study of rain itself, because altimeters can provide a finer spatial sampling of rain than can passive microwave instruments. However, there have been many varied implementations, using different records of the surface backscatter and different thresholds. This paper compares four different measures available for the recently-launched Jason-2. The evaluation compares these measures against clearly desired properties, finding that in most cases the adjusted backscatter and that from the ice retracker perform much better than that recommended in the users' handbook. The adjusted backscatter measure also provides a much better link to observations from Jason-1, opening up a much longer period for consistent rain investigations, and enabling greatly improved analysis of the short-scale variability of precipitation. Initial analysis shows that although the spatial and temporal gradients of backscatter increase at very low winds, the spatial gradients in rain attenuation are concentrated where rainfall is greatest, whilst the temporal changes have a simple broad latitudinal pattern
Are rain gauges in the right place?
No full textRain gauges are a powerful tool to measure rain entering a watershed. When water flow through a watershed is modeled, these rainfall measurements are used as inputs. Hydrological models have become increasingly complex as they more accurately represent the physical processes occurring. This is mostly done by increasing the spatial and temporal resolution of the model. As this resolution is increased, the inputs also need to increase. This thesis looks into if rain gauges are in the right place when used as inputs for hydrological models. This has been done by analysing four factors which literature showed to have affect rain gauges. The four considered factors are: the distribution of rain gauges, the steepness of the slope they are on, the location on that slope and their location within a watershed. For each of these factors algorithms have been developed in Python which compute relevant information on a given station. These algorithms have been applied to 368 gauges across the United Kingdom (UK), available from an open data source. The rain gauges are well distributed across different altitudes matching the distribution of heights across the UK. Above 400 m there are no gauges and this area is therefore underrepresented. The spacing of stations is good, a few close together and some isolated gauges on islands. The steepness of slopes varies strongly, when a steepness of 25% is used as a threshold only around 3% are on too steep of a slope. A fair amount of gauges are on ridges. Especially those near the coast have steep seaward slopes and thus will suffer from underestimating the actual rainfall. Within watersheds gauges are often near rivers causing other areas of the watershed to be underrepresented, especially areas of higher elevation. In future research it is recommended to use more gauges in the data set. Secondly focusing on a baseline comparison can help identify which stations are placed incorrectly. Lastly it is recommended to vary the resolution of elevation data and the spatial area considered, focusing on watersheds.GitHub containing used code - https://github.com/Daafip/Are-rain-gauges-in-the-right-placeCivil Engineerin
Sea state and rain: a second take on dual-frequency altimetry
No full textTOPEX and Jason were the first two dual-frequency altimeters in space, with both operating at Ku- and C-band. Each thus gives two measurements of the normalized backscatter, sigma0, (from which wind speed is calculated) and two estimates of wave height. Departures from a well-defined relationship between the Ku- and C-band sigma0 values give an indication of rain.This paper investigates differences between the two instruments using data from Jason's verification phase. Jason's Ku-band estimates of wave height are ~1.8% less than TOPEX's, whereas its sigma0 values are higher. When these effects have been removed the root mean square (r.m.s.) mismatch between TOPEX and Jason's Ku-band observations is close to that for TOPEX's observations at its two frequencies, and the changes in sigma0 with varying wave height conditions are the same for the two altimeters. Rain flagging and quantitative estimates of rain rate are both based on the atmospheric attenuation derived from the sigma0 measurements at the two frequencies. The attenuation estimates of TOPEX and Jason agree very well, and a threshold of -0.5 dB is effective at removing the majority of spurious data records from the Jason GDRs. In the high sigma0 regime, anomalous data can be cause by processes other than rain. Consequently, for these low wind conditions, neither can reliable rain detection be based on altimetry alone, nor can a generic rain flag be expected to remove all suspect data
Numerical simulation of the airflow–rivulet interaction associated with the rain-wind induced vibration phenomenon
No full textRain-wind induced vibration is an aeroelastic phenomenon that occurs on the inclined cables of cable-stayed bridges. The vibrations are believed to be caused by a complicated nonlinear interaction between rivulets of rain water that run down the cables and the wind loading on the cables due to the unsteady aerodynamic flow field. Recent research at the University of Strathclyde has been to develop a numerical method to simulate the influence of the external air flow on the rivulet dynamics and vice versa, the results of which can be used to assess the importance of the water rivulets on the instability. The numerical approach for the first time couples a Discrete Vortex Method solver to determine the external flow field and unsteady aerodynamic loading, and a pseudo-spectral solver based on lubrication theory to model the evolution and growth of the water rivulets on the cable surface under external loading. The results of the coupled model are used to assess the effects of various loading combinations, and importantly are consistent with previous full scale and experimental observations of rain-wind induced vibration, providing new information about the underlying physical mechanisms of the instability
Scenes of Rain: The Influence of Du Fu on Chen Yuyi's Poems on Rain
No full textIn classical Chinese literature, poems on the subject of rain started to appear during the Six-Dynasties period. Those poems were basically about farming and weather, and they can be broadly divided into two patterns; first, those that describe "suffering from rain" (ku yu 苦雨) and lament over long rains causing poor harvests, and second, those that describe "rejoicing over rain" (xi yu 喜雨) and cheer rain producing rich harvests. In the Tang period, Du Fu (712-770) brought several new dimensions to the descriptions of rain in poetry. First, Du Fu devoted himself to writing poems on the subject of rain, and he wrote far more poems on the subject than other contemporary poets. Second, Du Fu began to develop a new notion in poetics, namely that rain brings inspiration for poets, an idea that was adopted by other poets. The most notable feature of the poems that Du Fu wrote on rain, however, is that he took an interest in the serious problems facing society, such as wars and the suffering of the common people, while still adhering to the traditional two patterns of "suffering from rain" and "rejoicing over rain." Especially in his later works, the interior aspect of the poet and the outer world harmonized with each other, creating a symbolic world that integrates Du Fu's ironic self-presentation in the poetry into scenes of rain. A typical example is the poem "Rainy View from the Western Apartment" (Xige yuwang 西閣雨望). Later, in the period between the end of the Northern Song Dynasty and the beginning of the Southern Song Dynasty at the early twelfth century, the poet Chen Yuyi (1090-1138) also wrote many poems on rain, just as Du Fu did. During the first half of Chen's life, he was strongly influenced by the Jiangxi School 江西詩派 as evidenced by his use of techniques such as classical allusion, poetic diction, and couplet, and he was already skilled at imitating Du Fu's works by interweaving the predecessor poet's verses with his own. When the Jingkang Incident 靖康之變 broke out in 1126, leading to the collapse of the Northern Song Dynasty, Chen Yuyi roamed around South China to stay away from the war. In the second half of his life, Chen Yuyi realized the true value of Du Fu's late poetry after going through a bitter experience similar to what Du Fu had experienced in the An-Shi Rebellion 安史之亂, and he changed his poetry style. Chen Yuyi began to use extremely symbolic images in his poems on rain while also projecting in his scenes of rain the "patriotism" that he had inside him. However, Chen Yuyi describes his sorrow deeply and quietly, as seen in the poem "In the Rain" (Yuzhong 雨中), rather than the irony and self-mockery that Du Fu described
Programmatic and performance observations for Two Chamber Works by Chen Yi
No full textAs a Chinese-American composer who was born and reared in China, then studied and settled in the United States, Chen Yi’s success is widely recognized around the world. However, this success is not coincidental and is closely related to her fusion of the Chinese and Western cultures in her works. At the time of this writing, Chen Yi has composed more than forty chamber works, from which the author researched two with the same instrumentation—flute, clarinet, violin, cello, and piano. By understanding Chen Yi’s life experiences and analyzing the theoretical aspects of these compositions, the author gives suggestions for ensemble, timbre, rhythm, pedaling, and performance techniques in these two chamber works by Chen Yi—Happy Rain on a Spring Night and … as like a raging fire
Acid Rain - 02
No full textDocument - An article written by Martha Kostuch entitled, The Sour Side of Acid Rain, and letters from Martha Kostuch about acid rain. Brief to the Subcommittee on Acid Rain of the Standing Committee on Fisheries and Forestry (9 pages
Chou Chin-Chen\ue2s object-describing lyrics
No full textThe thesis focuses on the object-describing lyrics written by Chou Chin-Chen and investigates the selection of ideas, analysis of images, and artistic characteristics. This thesis is divided into six chapters.
Chapter 1 is divided into two sections. The first section introduces the research motivation, the research methods, and literature review. The second section studies the origin of object-describing lyrics to describe the relationship of objects and literature and to define the concept of object-describing lyrics.
Chapter 2 indicates the formation background of Chou Chin-Chen\ue2s lyrics. The first section discusses the historical origin and litery development of object-describing lyrics in terms of different dynasties: Early Chin dynasty, The Han dynasty, and Wei-Jin Dynasty. In addition, the section further investigates the civil object-describing lyrics in Dunhuang and intellectuals\ue2 object-describing lyrics in early North Song Dynasty. The second section discusses the factors of writing with the respect of the social and cultural background and makes the list of Chou Chin-Chen\ue2s lyrics in order to compare the background influences and literature characteristics.
Chapter 3 analyzes the content of Chou Chin-Chen\ue2s lyrics based on the definition made in the previous sections. The chapter discusses 32 lyrics to analyze the selection of ideas with six categories: season, plants, nature, appearance and time. There are two seasonal lyrics (lantern and Chongjiu festivals), ten plant lyrics (plum flowers, willows, pear, lotus, sweet-scented osmanthus, and apricot), seven nature lyrics (snow, moon, and spring rain). The discussion focuses on the image analysis including prototypes and trends and further investigates the historical backgrounds, content structures, writing skills and historical evaluations.
Chapter 4 studies and compares Chou Chin-Chen\ue2s object-describing lyrics in terms of the artistic characteristics, rhetoric skills, language styles, and content structures.
Chapter 5 describes the comments and influences of Chou Chin-Chen\ue2s object-describing lyrics. Chapter 6 concludes the achievement of Chou Chin-Chen\ue2s object-describing lyrics
Complex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L)
No full textComplex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L) were studied in a pot experiment by measurement of fresh weights of the plants, determination of surperoxide dismutase (SOD), peroxidase (POD), and lipid peroxidation (MDA) in the plant organs, and observation of injury symptoms. The experimental results demonstrated that all treatments of Cd2+, Zn2+, and/or acid rain significantly decreased fresh weights of kidney bean and caused toxic effects on growth of the plants, especially higher amounts of Cd2+ and Zn2+ and higher acidity of acid rain. Combination of these three pollutant factors resulted in more serious toxic effects than any single pollutant and than combinations of any two pollutants. SOD, POD, and MDA in the plant organs changed with different pollution levels, but MDA content in the leaves showed the best relationship between the pollution levels and toxic effects
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