Rainfall Infiltration Process of a Rock Slope with Considering the Heterogeneity of Saturated Hydraulic Conductivity

In order to analyze the effects of rainfall events on the stability of an open-pit rock slope, with considering the spatial variability of saturated hydraulic conductivity, based on the unsaturated seepage theory and the random filed theory, modified functions of the unit saturation, the hydraulic conductivity (k), and the shear strength parameters are established for unsaturated slope, by using FISH and the non-intrusive stochastic method. A saturated-unsaturated seepage random field model is proposed. And then the impacts of the rainfall intensity, the rainfall duration, and the spatial variability of saturated hydraulic conductivity (ks) on the infiltration process and stability of the unsaturated rock slope are analyzed. The results show that the proposed model can estimate rainfall infiltration of rock slope accurately. Rainfall mainly affects the seepage field in the shallow layer of the slope, where a transient saturated zone can be formed. With the development of the rainfall duration, the weight of the rock mass increased, the matric suction reduced, the negative pore pressure, the degree of saturation, and the infiltration depth of the rock slope increased, and the water in the slope root connects with the initial water table gradually, the unsaturated zone shrinks, which causes the safety factor of the model decreases, but the trend of change slows down gradually. As the rainfall intensity strengthened, the infiltration depth increased and the safety factor of the slope reduced, while the changing rate increases first and then decreases. Increasing the correlation length of k can reduces the infiltration depth and safety factor of the slope. Increasing the variation coefficient of k will increase the infiltration depth, while the safety factor of the slope decreases. The infiltration depth and safety factor of the slope are most affected by rainfall duration, but its sensitivity to the variability coefficient of k will be strengthened when the rainfall intensity exceeds the infiltration capacity. This conclusion can provide reference significance for the risk estimation of slope geological hazards, which are induced by the rainfall infiltration.

Modeling of the Marine atmosphere and its impact on Ka-band channels

The sea atmosphere environment will affect the Ka frequency channel in TT&C. Firstly, this paper briefly introduces the Marine atmospheric environment. Attenuation models of water vapor solubility and rainfall intensity are established. The variation characteristics of atmospheric environment and the estimation method of rainfall intensity are studied. Finally, the influence of Marine atmosphere on Ka-band channel is simulated and analyzed. The simulation results show that different elevation angles have different effects on Ka-band channels. The influence result decreases gradually with the elevation Angle increasing.

Changes in Rainfall and Climate Classification in South Sulawesi

The study discuss about Changes in Rainfall and Climate Classification in South Sulawesi. The climate of the Earth is determined by the location of the sun in relation to the earth's surface. Geographical location influences the categorization of climate on our planet. The results of the study (1) Rainfall in Bone Regency has been classified as high rainfall intensity for the last 10 years; (2) Determination of climate classification can be done by processing rainfall data obtained from data before weighting, after weighting, ranking, and opportunity; (3) The climate classification according to Schmidt-Ferguson for Bone Regency has a B climate type, which is a humid subtropical climate; and (4) The climate classification according This is based on a comparison of the number of dry months (BK) and wet months (BB), from which the Q value is obtained, which is then used to determine the type of climate according to Schmidt-Ferguson; (4) Oldeman's climate classification for Bone Regency has a C1 climate type, which has the characteristics of planting lowland rice once a year and secondary crops twice a year; (5) Oldeman's climate classification for Bone Regency has a This is based on the number of Wet Months (BB) and Dry Months (BK) in a given year

Spatial and temporal variations of rainy days and mean daily rainfall intensity in northern Nigeria.

The spatial and temporal variations of rainy Gays arid daily rainfall intensity for northern Nigeria for using 54 years data are analysed, The extent and nature of non-random changes, such as trend and fluctuations are Investigated. In general, both, the rainy day frequency and mean daily rainfall intensity decreases northwards except for localized orographic effect in the north central Part of the region. There is statistical evidence or decreasing trend in the, number of rainy days over the period of study, but the trend analysis showed no significance or the mean daily rainfall intensity. This suggests that the recent decreasing rainfall trend In the region particularly In the Sahellan zone, In the result of decrease In the frequency of rainy days and not due to any significant change In the rainfall intensity.

Decadal Study of Changing Frequency and Intensity of Rainfall for Selected Locations of Tamil Nadu

Understanding the pattern of regional climatic extremes is essential for creating an important adaptation measure to safeguard farmers from monsoon tantrums. This paper focuses on the rainfall variability and intensity for spatially different locations of Tamil Nadu. The daily rainfall data over a period of 30 years (1990-2019) for the study locations were collected from the constituent research centres of TNAU. The results indicated that an increasing trend in SWM rainfall was observed in Coimbatore (209.3 to 300.6mm), Ooty (681.4 to 703.1mm), Aduthurai (227.8 to 320.6mm), Kovilpatti (132.8 to 141.3 mm) while the decreasing trend was observed in rest of the places. A decreasing trend was reported in general for all the places during NEM. The decreasing trend in the number of rainy days was registered in Kovilpatti, Virudhunagar and Killikulam that exhibits an alert in modifying the crop planning programme in those areas. The frequency of rainfall intensity revealed that except Ooty, the number of Heavy Rain (HR) to VHR(VHR) was found to be meagre to absent in most of the study locations.

Coaction of Wind and Rain Effects on Large-Span Hyperbolic Roofs

Rainfall is often accompanied by strong winds. The large-span roof structure has a low height, its surrounding turbulence is high, and the wind speed changes greatly. The effects of coaction of wind and rain on the roofs cannot be ignored. Wind-driven rain (WDR) is an oblique movement phenomenon of raindrops generated by wind flow. Four types of hyperbolic roofs, that is, square, rectangular, circular, and elliptical, are selected as the objective to study the wind-driven rain by CFD simulation. Effects of wind direction, wind speed, and rainfall intensity on the WDR are analyzed. Pressure distribution of four types of hyperbolic roofs under coaction of wind and rain is obtained. The results are compared with those from the wind action only. The roofs are partitioned to obtain the coaction of wind and rain pressure of the four large-span hyperbolic roofs with different shapes under the most unfavorable working conditions. The results show that the average pressure coefficient of the roof surface increases with the increase of wind speed and rainfall intensity. The reference value of the average pressure coefficient of wind-driven rain on the surface of the roof is given, which provides a reference basis for the design of wind-driven rain on similar hyperbolic roofs.

WRF Rainfall Modeling Post-Processing by Adaptive Parameterization of Raindrop Size Distribution: A Case Study on the United Kingdom

Raindrop size distribution (RSD) is a key parameter in the Weather Research and Forecasting (WRF) model for rainfall estimation, with gamma distribution models commonly used to describe RSD under WRF microphysical parameterizations. The RSD model sets the shape parameter (μ) as a constant of gamma distribution in WRF double-moment bulk microphysics schemes. Here, we propose to improve the gamma RSD model with an adaptive value of μ based on the rainfall intensity and season, designed using a genetic algorithm (GA) and the linear least-squares method. The model can be described as a piecewise post-processing function that is constant when rainfall intensity is <1.5 mm/h and linear otherwise. Our numerical simulation uses the WRF driven by an ERA-interim dataset with three distinct double-moment bulk microphysical parameterizations, namely, the Morrison, WDM6, and Thompson aerosol-aware schemes for the period of 2013–2017 over the United Kingdom at a 5 km resolution. Observations were made using a disdrometer and 241 rain gauges, which were used for calibration and validation. The results show that the adaptive-μ model of the gamma distribution was more accurate than the gamma RSD model with a constant shape parameter, with the root-mean-square error decreasing by averages of 23.62%, 11.33%, and 22.21% for the Morrison, WDM6, and Thompson aerosol-aware schemes, respectively. This model improves the accuracy of WRF rainfall simulation by applying adaptive RSD parameterization and can be integrated into the simulation of WRF double-moment microphysics schemes. The physical mechanism of the RSD model remains to be determined to improve its performance in WRF bulk microphysics schemes.

Hydrological Effects of Prefabricated Permeable Pavements on Parking Lots

Permeable pavements can infiltrate and reduce stormwater runoff in parking lots, but issues around long construction periods and proper maintenance still required proper research and further understanding. The application of precast concrete can help to solve this. In this study, precast concrete components were applied to the design of permeable pavements to form prefabricated permeable pavements. The laboratory study is one of the first to examine the hydrological effect of prefabricated pervious pavements in parking lots. Four kinds of permeable pavements were designed and manufactured. These had different materials (natural sand-gravel, medium sand) which comprised the leveling layer or different assembly forms of precast concrete at the base. Three scenarios of rainfall intensity (0.5, 1, and 2 mm/min) and three rainfall intervals (one, three, and seven days) were simulated using rainfall simulators. The initial runoff time, runoff coefficient, and runoff control rate of each permeable pavement were investigated during the process of simulating. Results showed that the initial runoff time was no earlier than 42 min, the maximum runoff coefficient was 0.52, and the minimum runoff control rate was 47.7% within the rainfall intensity of 2 mm/min. The initial runoff time of each permeable pavement was no earlier than 36 min when the rainfall interval was one day, whereas, the maximum runoff coefficient was 0.64, and the average runoff control rate was 41.5%. The leveling layer material had a greater impact on the hydrological effect of permeable pavements, while the assembly form of precast concrete had no significant effect. Compared with natural sand-gravel, when the leveling layer was medium sand, the runoff generation was advanced by 4.5–7.8 min under different rainfall intensities, and 7–10 min under different rainfall intervals. The maximum runoff coefficient increased with about 14.6% when the rainfall interval was one day. Among four kinds of permeable pavements, the type I permeable pavement had the best runoff regulation performance. The results revealed that all prefabricated permeable pavements used in this study had good runoff control performance, and this design idea proved to be an alternative for the future design of permeable pavements.

An alternative approach to estimate any subdaily extreme of rainfall and wind from usually available records

A wide variety of engineering applications requires the use of maximum values of rainfall intensity and wind speed related to short recording intervals, which can often only be estimated from available less exhaustive records. Given that many locations lack exhaustive climatic records that would allow accurate empirical correlations between different recording intervals to be identified, generic equations are often used to estimate these extreme values. The accuracy of these generic estimates is especially important in fields such as the study of wind-driven rain, in which both climatic variables are combined to characterise the phenomenon. This work assesses the reliability and functionality of some of these most widespread generic equations, analysing climatic datasets gathered since 2008 in 109 weather stations in Spain and the Netherlands. Considering multiple recording intervals at each location, it is verified that most of these generic estimations, used especially in the study of wind-driven rain, have functional limitations and can cause significant errors when characterising both variables for subdaily intervals and extreme conditions. Finally, an alternative approach is proposed to accurately extrapolate extreme values of both variables related to any subdaily recording interval in a functional manner and from any available records.