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Typhoon Bolaven caused significant damage with severe rainfall all over South Korea, including Cheju Island, which received more than 250 mm in 2 days in August 2012. It was regarded as the most powerful storm to strike the Korean Peninsula in nearly a decade. The rainfall-rate datasets were obtained from S-band radar operated by the Korea Meteorological Administration to be analyzed and compared with the mesoscale Cloud Resolving Storm Simulator (CReSS) model simulation. Multifractal analysis was conducted to understand the structure of the rainfall rate with height in the typhoon system. The radar rainfall data presented with strong intermittency across scales at lower altitudes (1 and 2 km) and a more homogeneous rainfall field at high altitude (5 km) with two parameters (fractal codimension and multifractality index). The statistical scaling moment function and maximal singularities show clear significant differences between radar and the CReSS model.

Distributions of drop sizes can be expressed as DSD = Nt × PSD, where Nt is the total number of drops in a sample and PSD is the frequency distribution of drop diameters (D). Their discovery permitted remote sensing techniques for rainfall estimation using radars and satellites measuring over large domains of several kilometers. Because these techniques depend heavily on higher moments of the PSD, there has been a bias toward attributing the variability of the intrinsic rainfall rates R over areas (σR) to the variability of the PSDs. While this variability does increase up to a point with increasing domain dimension L, the variability of the rainfall rate R also depends upon the variability in the total number of drops Nt. We show that while the importance of PSDs looms large for small domains used in past studies, it is the variability of Nt that dominates the variability of R as L increases to 1 km and beyond. The PSDs contribute to the variability of R through the relative dispersion of χ = D3Vt, where Vt is the terminal fall speed of drops of diameter D. However, the variability of χ is inherently limited because drop sizes and fall speeds are physically limited. In contrast, it is shown that the variance of Nt continuously increases as the domain expands for physical reasons explained below. Over domains larger than around 1 km, it is shown that Nt dominates the variance of the rainfall rate with increasing L regardless of the PSD.

It is well known that rainfall rate is enhanced over mountains due to orographic uplifting. It would be beneficial to rainfall nowcasting if the intensity of the orographic enhancement could be estimated using simple parameters. In the present study, we found a clear relationship between orographic enhancement of the rainfall rate and the movement speed of radar echoes in a case study of rainfall over mountains in the southwestern area of the Kanto District in Japan during Typhoon 0709, by using rainfall data derived from X-band polarimetric radar. The increasing rate of rainfall rate per unit altitude (ΔR/ΔH) showed a positive correlation (r = 0:95) with the movement speed of radar echoes (V) when V > 10 m s-1. Such a correlation suggests that V is an effective parameter for quickly estimating the orographic enhancement of rainfall, however, more case studies are required before it can be used in practical applications.

Tropical cyclones, also known as typhoons or hurricanes, are among the most devastating events in nature and often strike the western North Pacific region (including the Philippines, Taiwan, Japan, Korea, China, and others). This paper focuses on addressing the rainfall retrieval problem for quantitative precipitation forecast during tropical cyclones. In this study, Special Sensor Microwave Imager (SSM/I) data and Water Resources Agency (WRA) measurements of Taiwan were used to quantitatively estimate precipitation over the Tanshui River basin in northern Taiwan. Various retrievals for the rainfall rate over land are compared by five methods/techniques. They are the single-channel regression, multichannel linear regressions (MLR), scattering index over land approach (SIL), support vector regression (SVR), and the proposed SIL–SVR. This study collected 70 typhoons affecting the studied watershed over the past 12 years (1997–2008). The measurements of the SSM/I satellite comprise the brightness temperatures at 19.35, 22.23, 37.0, and 85.5 GHz. Overall, the results showed the approaches using the SVR and conjoined SVR and SIL performed better than regression and SIL methods according to their performances of the root-mean-square error (RMSE), bias ratio, and equitable threat score (ETS).

The knowledge of 1-minute rainfall rate distribution is very important in order for the prediction of rainfall attenuation at any location. Due to the availability of 1-minute rainfall rate data is limited, conversion of rainfall rate distribution over a long integration time into the distribution for 1-minute is needed. Therefore several rainfall rate conversion methods were proposed.

Seasonal and spatial variation of the vertical gradient of rainfall rate was investigated using global precipitation data observed by the Precipitation Radar (PR) on the Tropical Rainfall Measuring Mission (TRMM) satellite. The vertical gradient was rendered by features of downward decreasing (DD) or downward increasing (DI) rainfall rate in the lower part of the profile. The DD profiles dominated tropical interior landmasses such as Africa and the Brazilian Plateau in summer. The DI profiles were observed over land in winter and over ocean except for regions with very little rainfall. In addition, DI profiles appeared during the height of the wet season even over the tropical landmasses, such as the mature monsoon period over inland India and over the Amazon River basin. Individual precipitation systems were also investigated in terms of their areally averaged DD and DI characteristics mainly over India. Deep (shallow) profiles tended to be DD (DI) for all seasons except the premonsoon season. A...

The cumulative distributions of rain intensity for 12 locations in South Africa are presented in this paper based on 5-year rainfall data. The rainfall rate having an integration time of 60 minutes is converted to the ITU-R recommended integration time of 1 minute for Durban in South Africa. Consequently, values of coefficients a and b so determined are used to convert 60-minute into 1- minute rain rates for other regions of South Africa. The resulting cumulative rain intensities are compared with the relevant ITU-R Recommendation P837. Based on this, an additional three rain zones are determined alongside the five ITU-R rain zones for South Africa.

The liquid/ice water paths (LWP/IWP) and the rainfall rate (RR) of precipitation systems over oceans are estimated using a combination of data from the special sensor microwave/imager (SSM/I) and the International Satellite Cloud Climatology Project (ISCCP). The retrieval scheme is based on microwave radiative transfer simulations. Collocated ISCCP cloud top temperatures are used to separate warm from cold precipitating clouds: cold precipitating clouds occur much more frequently than warm precipitating clouds and produce over 80% of the precipitation, but warm precipitating clouds are not negligible in the tropics and summer midlatitudes. SSM/I data are used to identify precipitating clouds: precipitating clouds are very rare (about 5% of all locations). Estimated IWP values, with mean about 7 mg/cm2, are quite variable, ranging from as little as 5 mg/cm2 to as much as 200 mg/cm2. The mean LWP in precipitating clouds is approximately 80 mg/cm2, occasionally reaching 1000 mg/cm2. Average RR (both cold and warm) is about 1.5 mm/hr, generally larger in the tropics than in midlatitudes. RR is larger in the northern hemispheric midlatitudes than in the southern midlatitudes. The global annual cycle of precipitation is dominated by tropical variations and is in phase with boreal seasons. The largest annual total precipitation occurs in the eastern Pacific (about 5000 mm). The subtropical precipitation minima may be underestimated because drizzle does not produce strong microwave signals.

[1] A stochastic model of rainfall rate is used to examine the temporal variability of rainfall during heavy convective rain periods. The model represents the microstructure of rainfall rate at time scales that are important for land surface processes associated with infiltration and runoff production. The representation of rainfall rate is based on a marked point process model of raindrop size distributions, which yields a gamma raindrop spectrum with parameters that are time-varying stochastic processes. Raindrop size distribution observations from a Joss-Waldvogel disdrometer in Princeton, New Jersey, during the period May–October 2006 are used along with the stochastic model to examine rainfall rate variability. Analyses focus on a sample of 60-min time periods in which heavy convective rainfall occurred. Central elements of the analyses entail examination of the relationships between rainfall rate and the time-varying model parameters that characterize the raindrop size distribution. We also examine the dependence structure among these processes. “Scaling law” formulations of raindrop size distributions are used to examine variability of raindrop size distributions. Analyses of the Princeton heavy rainfall periods also point to seasonal and diurnal heterogeneities as important elements of the distribution of extreme rainfall rates. Convective intensity, as reflected in cloud-to-ground lightning observations, plays an important role in the distribution of extreme rainfall rates and the evolution of raindrop size distributions associated with heavy rainfall.

The artificial radioactivity in rain was measured as a function of rainfall rate. As a rule an inverse relationship was found between the specific activity and the rate of rainfall. A tentative explanation is given. DOI: 10.1111/j.2153-3490.1959.tb00049.x

On 22 June 1947, Holt, Missouri, experienced a world-record rainstorm when 304.8 mm (∼1 ft) of rain fell in 42 minutes. In this paper, evidence is presented that this extremely heavy rain may have been produced by cold frontogenesis aloft (CFA). It is shown that what was earlier analyzed as a surface cold front was probably a drytrough, and that CFA was located at 700 hPa east of the drytrough, close to the location of the squall line, that produced the record precipitation rate.

Weather radars are used to measure the electromagnetic radiation backscattered by cloud raindrops. Clouds that backscatter more electromagnetic radiation consist of larger droplets of rain and therefore they produce more rain. The idea is to predict rainfall rate by using weather radar instead of rain-gauges measuring rainfall on the ground. In an experiment during two days in June and August 1997 over the Italian-Swiss Alps, data from a weather radar and surrounding rain-gauges were collected at the same time. The neural SOM and the statistical KNN classifier were implemented for the classification task using the radar data as input and the rain-gauge measurements as output. The rainfall rate on the ground was predicted based on the radar reflections with an average error rate of 23%. The results in this work show that the prediction of rainfall rate based on weather radar measurements is possible. 2 1393 1396 Sponsors: IEEE Neural Networks Society, INNS Conference code: 64098 Cited By :3

In this paper, we present our contribution of rainfall rate and Ku-band rain attenuation measurements at Bandung. This measured data is an important complement to several of previous recorded data from other tropical cities in Indonesia for characterizing the Ku-band satellite propagation in tropical area. The two years of our experiment results indicate that the measured R0.01 rainfall rate at Bandung is 120 mm/h and the measured A0.01 rain attenuation is 17 dB. Therefore, the P region of ITU-R model is over estimated for Bandung, and we suggest that Q-region of ITU-R model is more suitable for Bandung. Another previous measurements which had performed in Indonesia confirmed with our conclusions that some cities in Indonesia have not only P-region of ITU-R model (such as Padang, Bengkulu an Makassar), but also N (Jayapura) and Q-region (Surabaya). Based on 10 samples rainfall rate in Indonesian archipelago, we have developed new prediction model of R0.01 value for Indonesian cities. Concerning to the rain attenuation statistics, we have found out, that the DAH model is valid for Indonesia. We also have found out that if Bandung is modelled by Q-region of ITU-R, we should include the wetting antenna effects as the correction factor to the the ITU-R model for confirming with the measured A0.01 rain attenuation

Diurnal cycles of summertime rainfall rates are examined over the conterminous United States, using radar-gauge assimilated hourly rainfall data. As in earlier studies, rainfall diurnal composites show a well-defined region of rainfall propagation over the Great Plains and an afternoon maximum area over the south and eastern portion of the United States. Zonal phase speeds of rainfall in three different small domains are estimated, and rainfall propagation speeds are compared with background zonal wind speeds. Unique rainfall propagation speeds in three different regions can be explained by the evolution of latent-heat theory linked to the convective available potential energy, than by gust-front induced or gravity wave propagation mechanisms.

The wave propagation at frequencies from about 10 GHz can suffer rain effects such as attenuation, scattering and depolarization. The magnitude of these effects depends on rain characteristics. This paper presents results of the propagation experiments undertaken in Douala (Cameroon) and in Brazzaville (Congo) under the auspices of the ITU (Geneva) with the collaboration of CNET (France Telecom). Data based on five months measurements of rain rates in Douala with a network of four rain-gauges are presented with reference also to some results of a propagation campaign in Brazzaville. The rain measurement period in Douala includes all of the rainy season. The measurement data are used to investigate the rain effect characteristics of the low latitude tropical regions of Africa and are discussed in relation to the influence of rain on microwave system performances in the region.

[Abstra ct] As an example of novel rain attenuation mitigation technologies categorized in the diversity methods , we analyzed a macroscopic time diversity method. This method makes use of the natural characteristics that rain never lasts forever. In th is time di versity method, a part or whole information is transmitted several times with a certain delay between transmissions . The receiver saves the several versions of the information in the memory and these versions are used complementarily. In order to evaluate the time diversity effect quantitative ly such as diversity gain which is applicable to all over Asian region especially in tropical one where many large rain -induced attenuation events are expected. For this purpose, we use AMeDAS rainfall data which is available all over Japan and rainfall data measured in Indonesia, tropical Asian region . We show the effect of time diversity and also compare time diversity gain s observed in Japan and Indonesia.

Rainfall rate data from three Norwegian sites, each representing different typical climates, are studied. The sites are compared with respect to % occurrence of rain rates, and also compared with curves calculated from the latest ITU recommendation. The duration of rain events when including different minimum rain rates are calculated, and a closed mathematical expression is presented for each of the three Norwegian sites. The variability of rain rates is discussed in terms of a 'long term stability" parameter.

A new global rainfall rate model has been developed for improving the accuracy of rain attenuation prediction in Earth-satellite and terrestrial links. The required meteorological parameters are the annual rainfall amount (mm), the probability of rainy 6 hour periods and the portion of convective-type rains from all rains. They have been calculated from the 6 hour rainfall forecasts of the European Centre for Medium-range Weather Forecasts (ECMWF) from October 1992 to September 1994. The accuracy of the two first parameters have been improved using also the precipitation data of the Global Precipitation Climate Project (GPCP) from 1986 to 1992. The new method was validated against rainfall rate data from about 60 sites including about 140 experiment years. The mean RMS-value of the relative differences between predicted and measured rainfall rates for time percentage range from 0.001 to 1% is about 28%, when ECMWF data together with GPCP-data has been used, and about 32%, when only the global ECMWF-data has been used. The corresponding difference between ITU-R rain zones and measured rainfall rates is about 39%. Further improvements could be obtained using more long-term data from the ECMWF rainfall forecasts than two years.

Numerous investigations have been made in the last two decades from both a direct measurement of the radar reflectivity and the rainfall amount, as well as indirect measurements of the raindrop size spectra. Calculations of the reflectivity factor and rainfall rate from these spectra can be made and the relationships determined. Both methods are discussed and a summary of the relationships presented. These relationships show differences in excess of 500% in rainfall rate at the same reflectivity. These large differences are primarily associated with differences in geographic locality. In addition, there are smaller differences on the order of 150% that can be attributed to different types of rain or different synoptic conditions. Some data are available which are indicative of the differences in the relationship on a given day, depending upon the location within the storm which is sampled. This is briefly described and in only one case out of 18 is there a significant difference. Estimates of the...

Raindrop-size distributions obtained with the drop camera have been used to determine rainfall rate-radar reflectivity relationships for nine different locations throughout the world. Since the climates sampled were quite varied, an extrapolation of these Z-R relationships to other areas of the world with similar “drop-spectra climates” can be performed. Two climatic parameters, the mean annual per cent of rain days that are thunderstorm days, and the mean annual relative humidity at 0.5 km above ground, were found to be highly correlated with the coefficient A and exponent b in the Z-R equation, Z = ARb. Regression equations based on the two climatic parameters were determined, permitting an estimation of the Z-R relationship for any area once the parameters are obtained.

Raindrop-size spectra obtained with the raindrop camera have been analyzed from two locations, Island Beach, N. J., and Franklin, N. C. The spectra were analyzed with respect to total number of drops per average rain rate per cubic meter of sample, geometric mean diameter, mode diameter, and the diameter of drops at which half the liquid water content lies above that diameter and half below. The results indicate that the distributions from both locations are quite similar for corresponding rainfall rates. Rainfall rate-radar reflectivity relationships indicate that cold frontal rains in these areas generally have smaller drops than warm frontal rains. In addition, it was found that upslope rains are composed of smaller drops than rains of similar synoptic conditions without upslope effects. Finally, a small sampling of a tropical storm rain revealed that small drops may be characteristic of this type of rain.

In evaluating the environmental limitations on microwave signal transmission, it was necessary to determine the occurrence of rainfall rates for a number of regions in different parts of the world. Clock-hourly precipitation data were used where available. Where these data were not available, a known empirical technique was employed which correlates clock-hourly rainfall at individual rates to a climatological index. This index uses parameters which are almost universally obtainable—namely, mean annual rainfall and number of days with measurable rain. In the course of this work, the authors found a more general relation between clock-hourly rainfall rate frequencies and the climatological index. Using this relation, rainfall frequencies at any rate are obtained directly from a linear equation and two nomograms. It is also possible to synthesize the complete frequency distribution of rainfall rates and obtain, as a check, the mean annual rainfall. Examples, supplemented by illustrations, are given in the development of this technique and its utilization.

800x600 Seasonal and diurnal variations of lightning activity over West Sumatra have been investigated using observations of Tropical Rainfall Measuring Mission–Lightning Imaging Sensor (TRMM–LIS) over a 16-year period. This study also used TRMM 3B43 and 2A25 data to observe the correlation between lightning activity with rainfall and precipitation type. Results show that lightning occurs more frequently over land than over ocean and coastal areas, in contrast to total rainfall, which is higher over ocean and coastal areas. The lightning pattern is similar to the convective rainfall (particularly deep convective) pattern, which indicates that the majority of lightning in West Sumatra is associated with deep convective rain. The lightning intensity in Indonesia during the convection period, namely, December–January–February and September–October–November, is higher than that during other periods. The diurnal cycle of lightning coincides with the diurnal cycle of cloud migration from the ocean to inland Sumatra, as reported in previous research. Lightning and deep convective precipitation are dominant during the day and evening (16.00–20.00 Local Standard Time [LST]), particularly over land. S tratiform precipitation occurs more frequently from afternoon to early morning (16.00–04.00 LST) over land and at 00.00–12.00 LST over the ocean. Normal 0 false false false EN-ID X-NONE X-NONE MicrosoftInternetExplorer4

The current study summarizes the raindrop size distributions (RSDs) characteristic of the North Indian Ocean (NIO) tropical cyclones (TCs) measured with ground-based disdrometers installed at the coastal (Thiruvananthapuram, 8.5335°N, 76.9047°E) and inland (Kadapa, 14.4742°N, 78.7098°E) stations in south India. The NIO TCs observed at the coastal station showed more mid- and large-size drops (>1 mm) than the inland station. On the other hand, for both inland and coastal stations, small and mid-size drops (

Considerando que o clima é a sucessão dos estados de tempo que se repetem e incidem ao longo dos anos, pode-se pensar nele como consequência primeira da interação entre os elementos e os fatores geográficos, que, por sua vez, respondem pela dinâmica atmosférica. Tal conhecimento contribui significativamente para o planejamento urbano e rural, pois revela, entre outros fatores, o regime da precipitação pluvial, a variação da temperatura, a velocidade e a direção dos ventos, a radiação solar e a umidade relativa do ar, que, associados à natureza da superfície, respondem por situações diversas. Neste trabalho, as chuvas têm posição de destaque, pois elas são as verdadeiras tradutoras do ritmo climático em áreas tropicais semiúmidas, como é o caso de Goiás. Nesse sentido, a dissertação teve como objetivo geral analisar o regime pluviométrico e compreender o ritmo de sucessão dos estados atmosféricos de caráter excepcional na região de Jataí, contribuindo, dessa maneira, para a caracterização climática da área de estudo. Esta pesquisa foi realizada à luz da Climatologia Geográfica, a partir de técnicas quantitativas (desvio quartílico, medidas de tendência central, pluviogramas de Schröder) e qualitativas (análise rítmica). Este estudo apresenta como resultado o regime climático da região e o índice de participação dos sistemas atmosféricos. As chuvas que ocorrem em Jataí estão ligadas, principalmente, a passagens frontais e à atuação das massas Tropical Atlântica com instabilidades e Equatorial Continental. Considering climate as the yearly sequence of weather patterns, it may be viewed as ultimate result of the interaction between geographic variables, these being responsible for the atmospheric dynamics. Such acknowledgment contributes significantly to urban and rural planning, as it indicates, among other elements, precipitation, temperature variation, wind speed and direction, solar radiation, and relative humidity, which when associated to the surface, respond for various climatic phenomena. In this research, rainfall is highlighted as the true indicator of weather patterns in tropical savanna climates, such the case of the Goiás state. In this sense, the research had as main objective to analyze the rainfall regime and comprehend the sucession rate of atmospheric states of exceptional nature in the Jataí region, thus contributing to the climatic profiling of the researched area. This work was undertaken by mold of the Geographic Climatology, from quantitative (quartile deviation, central tendency distributions, Schroeder's pluviograms) and qualitative (rhythmic analysis) techniques. The study presents as conclusion the region's climatic regime and the atmospheric systems' participation table. The rainfall in Jataí is related, mainly, to frontal passings and action of an unstable Tropical-atlantic and Equatorial-continental air mass.

An ensemble of 20 extended integrations of the atmospheric model CSIRO Mark 2, forced with the sea surface temperature observed during the 1986–1998 period, was performed to analyze the simulation capability of seasonal climate anomalies over South America and adjacent oceanic areas. Variations of the simulation skill within the region and during the experimental period were assessed through standard statistical measures and compared to the signal-to-noise ratio distribution. Before the skill assessment, model systematic errors were thoroughly evaluated. The results confirm that the simulation skill is very high in tropical oceanic areas, and decreases rapidly towards middle and high latitudes. Model performance at mid and high atmospheric levels is substantially better than at low levels. Relatively high simulation capability was found over the Pacific Ocean between the equator and the Antarctic coast, which is coherent with the presence of three relative maximums in the signal-to-noise ratio, similar to the increase of the forced variance found by several authors over much of the Pacific–North American pattern region. Rainfall rate and second-order moments associated with the cyclonic activity and the meridional eddy fluxes of heat and humidity are better simulated in a narrow strip parallel to the SPCZ and extending further southeast into mid latitudes of the continent. The simulation skill noticeably improves during the warm and cold ENSO phases, in correspondence with an intensification of the signal-to-noise ratio, and useful rainfall anomaly simulations can be obtained over the Amazonas and Rio de la Plata river basins. Fil: Labraga, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina

International audience; The response of photosynthetic activity to interannual rainfall variations in Africa South of the Sahara is examined using 20 years (1981-2000) of Normalised Difference Vegetation Index (NDVI) AVHRR data. Linear correlations and regressions were computed between annual NDVI and annual rainfall at a 0.5° latitude/longitude resolution, based on two gridded precipitation datasets (Climate Prediction Center Merged Analysis of Precipitation [CMAP] and Climatic Research Unit [CRU]). The spatial patterns were then examined to detect how they relate to the mean annual rainfall amounts, land-cover types as from the Global Land Cover 2000 data set, soil properties and soil types. Yearly means were computed starting from the beginning of the vegetative year (first month after the minimum of the NDVI mean regime), with a one-month lead for rainfall. One third of tropical Africa displays significant (95% c.l.) correlations between interannual NDVI variations and those of rainfall. At continental scale, soil types and soil properties are only minor factors in the overall distribution of the correlations. Mean annual rainfall amounts and land-cover types are much more discriminating. The largest correlations, mostly over 0.60, are distinctly found in semi-arid (200-600 mm annual rainfall) open grassland and cropland areas. The presence of one of these two determinants (semi-aridity, and favourable land-cover type, i.e. open grassland and cropland) in the absence of the other does not systematically result in a significant correlation between rainfall and NDVI. By contrast, NDVI variations are independent from those of rainfall in markedly arid environments and in most forest and woodland areas. This results from a low signal-to-noise ratio in the former, and the fact that precipitation is generally not a limiting factor in the latter. The marginal response of NDVI to a given increase/decrease in rainfall, as described by the slope of the regression, displays a similar pattern to that of the correlation, with maximum slopes in semi-arid regions, except that a weaker response is noted in more densely populated areas, suggesting an incidence of particular land-use and agricultural practises. One-year lag relationships between annual rainfall and NDVI in the next year were also considered. Ten percent of the grid-points show significant correlations, but the spatial patterns remain difficult to interpret.

This study aims to obtain the rate of rainfall (RR) over ocean areas using satellite data by establishing the relationship between Advanced Microwave Sounding Unit-A (AMSU-A) microwave brightness temperature (Tbs) data and island rain gauge rainfall. This study applied a rain identification technique developed by Grody et al. (1999) using AMSU-A data accepted to screen rain events over ocean areas. Using rain gauge data of Sakishima-shoto in Japan as a ground truth, validation of rain identification was conducted every May and June from 1999 to 2001. Including times of both rainfall and no rainfall, the overall rates of successful recognition were 87.3%, 87%, and 89% for 1999, 2000, and 2001, respectively. As for quantitative validation, the coefficient of determination was 0.72. To obtain further precipitation observations, another rainfall estimation retrieved by the TRMM Microwave Imager (TMI) data onboard the Tropical Rainfall Measuring Mission (TRMM) was compared with the AMSU-A data. The results displayed solid agreement in rainfall patterns and rain distribution. Additionally, when the AMSU-A RRs were multiplied by a factor of approximately 1.5 (particularly for heavy rainfalls), the intensities of the AMSU-A RRs roughly equaled those of the TMI RRs. Combining this data with the other satellite rainfall retrieval data, a series of AMSUA rain maps for sea areas were shown to mitigate the problem of relatively sporadic observations of rainfall at sea.

International audience; The Madden-Julian Oscillation (MJO) was shown in Part I to have a significant impact on both East African rainy seasons at pentad time-scale. The case of the 'long rains' (March-May) is further examined by considering both shorter (daily) and longer (interannual) time-scales. Based on composite analyses, extreme daily rainfall events in the Highland (west) and in the coastal (east) regions of Equatorial East Africa (Kenya and Tanzania) are extracted. Low-level westerly wind anomalies are seen to accompany wet events in the west and easterly ones in the east. These opposite circulation anomalies preferentially occur at distinct phases of the MJO, which indicates that the latter has a major influence on rainfall at the daily time-scale. However, this influence undergoes significant year-to-year variations. It is found that the common variance between smoothed rainfall time series (5-day low-pass filter) and MJO indices varies from 5% to 53% in the Highland region. Significantly lower air temperatures in the upper troposphere are recorded during the MJO cycles that present the highest common variance with East African rainfall. Such a cooling is seen to be related to the Kelvin wave propagation in the upper layers which favours upward atmospheric motion over the region. At the interannual time-scale, fluctuations in MJO amplitude contribute to the March-May rainfall variability, and 44% of the March-May seasonal rainfall variance in the 1979-95 period in East Africa is explained by this parameter. Years of high MJO amplitude are characterized by earlier onset of the rains, and higher seasonal amounts.