Small Amounts Of Rain Research Articles

The Brettenham storm of 25 July 2021

The <scp>Brettenham</scp> storm of 25 <scp>July</scp> 2021

Assessment of Groundwater Recharge Potential Depending on Morphologic Analysis in East of Wasit, Southeastern Iraq

Modern technologies are used for watershed management to cope with drought risks in arid and semi-arid regions. The study aimed to conduct a morphometric analysis and know potential groundwater recharge areas in the eastern region of Wasit Province. Remote sensing and GIS data were used for morphometric analysis. The morphometric analysis results adopted the Digital Elevation Model. The results of the analysis were verified by matching the results with what exists in reality. The area of the first basin was 1482.017, as it is the largest basin from the area, with a percent of 51.228% of the total area of all basins. The percentage of first-degree flows reached 83.37% in the first basin, 74.14% percent in the second basin, 75.51% in the third basin, and 75.75% in the fourth basin from all streams in each basin. The bifurcation rate (3.135-4.233), Stream frequency range values (0.543-0.332), drainage texture coarse, low drainage density that ranged between 0.986-1.14 km/km2 elongation ratio ranging from 0.348-0.624 form factor (0.095-0.316). The basins' circularity (0.105-0.238) relief value (951-112) m infiltration number value (0.369-0.535). All basins have a longitudinal shape and lead to the formation of floods and rapid currents, which exposes the region to rapid seasonal floods and the creation of flash floods that cause soil erosion and analyses the drainage intensity results. It was low, and this is an indication that the ground has high permeability. The flow frequency results indicate that the area is semi-arid and exposed to small amounts of rain and coarse drainage texture by comparing the result parameters from morphometric analysis results for each basin. The potential recharge areas of groundwater in the study area can be known, n as the analysis results showed that recharge potential occurs in all basins. The highest groundwater recharge is possible in the third basin and the lowest in the first basin. Morphometric analysis was performed by ARC-GIS(Arc-map10.4).

Moisture Dry-Out Capability of Steel-Faced Mineral Wool Insulated Sandwich Panels

Moisture dry-out from steel-faced insulated sandwich panels has previously received little attention from researchers. This paper reports the results from laboratory tests and dynamic heat, air, and moisture transport simulations of the moisture dry-out capabilities of a steel-faced sandwich panel with a mineral wool core. Three test walls (TWs) with dimensions of 1.2 m × 0.4 m × 0.23 m were put above water containers to examine the moisture transport through the TWs. A calibrated simulation model was used to investigate the hygrothermal regime of a sandwich panel wall enclosure with different initial moisture contents and panel joint tightening tapes. The moisture dry-out capacity of the studied sandwich panels is limited (up to 2 g/day through a 30-mm-wide and 3-m-long vertical joint without tapes). When the vertical joint was covered with a vapour-permeable tape, the moisture dry-out was reduced to 1 g/day and when the joint was covered with a vapour-retarding tape, the dry-out was negligible. A very small amount of rain would be enough to raise the moisture content to water vapour saturation levels inside the sandwich wall, had the rain ingressed the enclosure. The calculated time of wetness (TOW) on the internal surface of the outer steel sheet stayed indefinitely at about 5500 h/year when vapour-retarding tapes were used and the initial relative humidity (RH) was over 80%. TOW stabilised to about 2000 h/year when a vapour-permeable tape was used regardless of the initial humidity inside the panel. A vapour-permeable tape allowed moisture dry-out but also vapour diffusion from the outside environment. To minimise the risk of moisture damage, avoiding moisture ingress during construction time or due to accidents is necessary. Additionally, a knowledge-based method is recommended to manage moisture safety during the construction process.

Rapid plastic breeding response to rain matches peak prey abundance in a tropical savanna bird.

Changes in climate are shifting the timing of life cycle events in the natural world. Compared to northern temperate areas, these effects are relatively poorly understood in tropical and southern regions, where there is limited information on how timing of breeding and food availability are affected by climatic factors, and where patterns of breeding activity are more unpredictable within and between years. Combining a new statistical modelling approach with 5years of continuous individual-based monitoring of a monsoonal tropical insectivorous bird, we quantified (a) the proximate climatic drivers at two trophic levels: timing of breeding and abundance of arthropod prey; (b) the effect of climate variation on reproductive output and (c) the role of individual plasticity. Rainfall was identified as the main determinant of phenology at both trophic levels. Throughout the year, likelihood of egg laying increased very rapidly in response to even small amounts of rain during the preceding 0-3weeks. Adult body mass and male sperm storage also increased rapidly after rain, suggesting high breeding preparedness. Additionally, females were flexible, since they were more likely to nest whether their previous attempt was longer ago and unsuccessful. Arthropod abundance also increased after rainfall, but more slowly, with a peak around 10weeks. Therefore, the peak food availability coincided with the presence of dependent fledglings. Fitness benefits of nesting after more rain appeared to be linked to offspring quantity rather than quality: nest attempts following higher rainfall produced larger clutches, but showed no improvement in nestling mass or relative fledging success. The response of clutch size to rainfall was plastic, since repeated sampling showed that individual females laid larger clutches after more rain, possibly mediated by improved body mass. Rapid, individually flexible breeding in response to rainfall and slower increase in arthropod abundance also as a response to rainfall, might buffer insectivorous species living in tropical seasonal environments from climate change-induced phenological trophic mismatches.

Cloud droplet growth in shallow cumulus clouds considering 1-D and 3-D thermal radiative effects

Abstract. The effect of 1-D and 3-D thermal radiation on cloud droplet growth in shallow cumulus clouds is investigated using large eddy simulations with size-resolved cloud microphysics. A two-step approach is used for separating microphysical effects from dynamical feedbacks. In step one, an offline parcel model is used to describe the onset of rain. The growth of cloud droplets to raindrops is simulated with bin-resolved microphysics along previously recorded Lagrangian trajectories. It is shown that thermal heating and cooling rates can enhance droplet growth and raindrop production. Droplets grow to larger size bins in the 10–30 µm radius range. The main effect in terms of raindrop production arises from recirculating parcels, where a small number of droplets are exposed to strong thermal cooling at cloud edge. These recirculating parcels, comprising about 6 %–7 % of all parcels investigated, make up 45 % of the rain for the no-radiation simulation and up to 60 % when 3-D radiative effects are considered. The effect of 3-D thermal radiation on rain production is stronger than that of 1-D thermal radiation. Three-dimensional thermal radiation can enhance the rain amount up to 40 % compared to standard droplet growth without radiative effects in this idealized framework. In the second stage, fully coupled large eddy simulations show that dynamical effects are stronger than microphysical effects, as far as the production of rain is concerned. Three-dimensional thermal radiative effects again exceed one-dimensional thermal radiative effects. Small amounts of rain are produced in more clouds (over a larger area of the domain) when thermal radiation is applied to microphysics. The dynamical feedback is shown to be an enhanced cloud circulation with stronger subsiding shells at the cloud edges due to thermal cooling and stronger updraft velocities in the cloud center. It is shown that an evaporation–circulation feedback reduces the amount of rain produced in simulations where 3-D thermal radiation is applied to microphysics and dynamics, in comparison to where 3-D thermal radiation is only applied to dynamics.

Differential effect of shade, water and soil type on emergence and early survival of three dominant species of the Atacama Desert

AbstractUnderstanding the regeneration niche of species may allow us to gain insight into how communities are structured. In deserts, the regeneration niche is usually related to spaces beneath shrubs where shade cast by shrubs creates microenvironments that benefit seedlings and where even small amounts of rain may favour germination and establishment. Shade and water may also interact with different types of soils. However, species may have different requirements for germination and seedling survival. We could expect that shrub species with different drought tolerances exhibit different responses to the combination of these factors. We ask if responses of dominant species of the Atacama Desert to abiotic factors (shade, water and soil type) are related to their drought tolerance, a topic not exhaustively explored in shrubs growing in true deserts. We conducted two factorial experiments. The first one was designed to evaluate how shade (microhabitat) in combination with water may affect germination (emergence) and early survival. In the second experiment, we assessed the influence of shade in relation to soil type. Each species responded distinctively to the three variables under study, but in general, their emergence responses were more influenced by water (more water, greater emergence) than by microhabitat or soil type. Survival was influenced both by microhabitat and by water and was higher under shade and abundant water. Soil type affected only one of our species in terms of emergence. Species responses in general depended on their tolerance to stress. In one species, there was indication of a seed–seedling conflict. Our results show similar species responses to environmental constraints but also more or less unique responses that are related to their tolerance to drought and which may ultimately permit species coexistence. We found that shade may not be important for germination but may be crucial for survival in dry years.

Requirements and limits for life in the context of exoplanets.

The requirements for life on Earth, its elemental composition, and its environmental limits provide a way to assess the habitability of exoplanets. Temperature is key both because of its influence on liquid water and because it can be directly estimated from orbital and climate models of exoplanetary systems. Life can grow and reproduce at temperatures as low as -15 °C, and as high as 122 °C. Studies of life in extreme deserts show that on a dry world, even a small amount of rain, fog, snow, and even atmospheric humidity can be adequate for photosynthetic production producing a small but detectable microbial community. Life is able to use light at levels less than 10(-5) of the solar flux at Earth. UV or ionizing radiation can be tolerated by many microorganisms at very high levels and is unlikely to be life limiting on an exoplanet. Biologically available nitrogen may limit habitability. Levels of O2 over a few percent on an exoplanet would be consistent with the presence of multicellular organisms and high levels of O2 on Earth-like worlds indicate oxygenic photosynthesis. Other factors such as pH and salinity are likely to vary and not limit life over an entire planet or moon.

ANNUAL RHYTHM AND POSITION EFFECT IN THE GERMINABILITY OF MESEMBRYANTHEMUM NODIFLORUM

Mesembryanthemum nodiflorum L. is an annual plant that inhabits the hottest and driest parts of Israel's deserts. This ombrohydrochoric plant requires only extremely small amounts of rain for seed release and dispersal near the dead mother plant (topochory). There is no relationship between rainfall required for seed dispersal and that needed for germination. Dry closed capsules were collected in 1972 and 1974 between Jericho and the Dead Sea, and stored in the laboratory. Germination tests during the summer of 1976 and the years 1978, 1979/80, revealed an annual rhythm in seed germinability which ensures that germination is restricted to winter, the normal rainy season. Within a capsule the outer seeds are released first and have higher germination percentages than the inner seeds. This position effect (heteroblasty), together with the topochory and annual rhythm, are related to the life cycle of this plant in its desert habitat.

Incidence and ecology of very fast germination

AbstractA group of flowering plant species is known to germinate in less than 24 h from imbibition, but this phenomenon is often overlooked in the current literature. Here, I review this topic by searching the literature published since 1967 and listing the 28 most detailed cases found. Of these, 20 are species of Amaranthaceae (all formerly treated as Chenopodiaceae); 15 of these are from the subfamily Salsoloideae, which is characterized by the possession of spiral embryos. The non-chenopods listed are small numbers of species from the families Acanthaceae, Cruciferae, Gramineae (one species) and Salicaceae (PopulusandSalix). Seeds of the Salsoloideae contain fully differentiated embryos. On imbibition, the embryo cells elongate and the spiral embryo uncoils and ruptures the thin seed coat. This can occur in as little as 10 min. Nearly all of the families showing very fast germination have small to very small seeds and little or no endosperm. Most species have soft, thin seed coats that imbibe water readily. All are from high-stress habitats, either arid or saline or from active floodplains, where they can rapidly exploit temporarily favourable conditions for germination. They exhibit one of two contrasting germination behaviours, either having seeds which all germinate within a very short time of wetting or having seed persistence whereby small amounts of rain cause germination of small fractions of seed from a long-living soil seed bank. Serious confusion in the literature in the use of the term ‘opportunistic’ is pointed out and clarified.

A novel application of natural fluorescence to understand the sources and transport pathways of pollutants from livestock farming in small headwater catchments

This paper demonstrates the application of a low-cost and rapid natural fluorescence technique for tracing and quantifying the transport of pollutants from livestock farming through a small headwater catchment. Fluorescence intensities of Dissolved Organic Matter (DOM) present in different pollutant sources and drainage waters in the Den Brook catchment (Devon, UK) were monitored through storm events occurring between January 2007 and June 2008. Contrasting fluorescence signals from different sources confirmed the technique's usefulness as a tracer of pollutants from livestock farming. Changes in fluorescence intensities of drainage waters throughout storm events were used to assess the dynamics of key pollutant sources. The farmyard area of the catchment studied was shown to contribute polluted runoff at the onset of storm events in response to only small amounts of rain, when flows in the Den Brook first-order channel were low. The application of slurry to a field within the catchment did not elevate the fluorescence of drainage waters during storm events suggesting that when slurry is applied to undrained fields the fluorescent DOM may become quickly adsorbed onto soil particles and/or immobilised through bacterial breakdown. Fluorescence intensities of drainage waters were successfully combined with discharge data in a two component mixing model to estimate pollutant fluxes from key sources during the January 2007 storm event. The farmyard was shown to be the dominant source of tryptophan-like material, contributing 61–81% of the total event flux at the catchment outlet. High spatial and temporal resolution measurements of fluorescence, possibly using novel in-situ fluorimeters, may thus have great potential in quickly identifying and quantifying the presence, dynamics and sources of pollutants from livestock farming in catchments.

Differences in the timing of germination and reproduction relate to growth physiology and population dynamics of Sonoran Desert winter annuals

Trait differences can promote distinct survival and fecundity responses to environmental fluctuations. In a Sonoran Desert winter annual plant community, we have identified a tradeoff between relative growth rate (RGR) and water-use efficiency (WUE) that predicts interannual variation in reproductive success. Here we test the hypothesis that traits underlying RGR and WUE differences are linked to seasonal phenology. We use long-term demographic data and finer-scale, short-term data to investigate timing of germination, reproduction, and death of several winter annual species in multiple years in open and under-shrub habitats. We hypothesized that species with high WUE and less interannual demographic variability would have life cycle transitions early in the winter to spring growing season. This would be due to an ability to use small amounts of rain and photosynthesize at low temperatures. By contrast, we hypothesized that species with low WUE whose survival and reproductive rates vary greatly from year to year would have life cycle transitions later in the season. In any given year, species with high WUE germinated and reproduced earlier in the season than species with low WUE, whereas low-WUE species germinated later and had shorter reproductive phases. Our results demonstrate a direct relationship between phenology and physiological trait differences. This link between phenology and physiology is of interest because it clarifies the mechanism by which trait differences determine species' relative abundances.

Modeling the impact of wintertime rain events on the thermal regime of permafrost

Abstract. In this study, we present field measurements and numerical process modeling from western Svalbard showing that the ground surface temperature below the snow is impacted by strong wintertime rain events. During such events, rain water percolates to the bottom of the snow pack, where it freezes and releases latent heat. In the winter season 2005/2006, on the order of 20 to 50% of the wintertime precipitation fell as rain, thus confining the surface temperature to close to 0 °C for several weeks. The measured average ground surface temperature during the snow-covered period is −0.6 °C, despite of a snow surface temperature of on average −8.5 °C. For the considered period, the temperature threshold below which permafrost is sustainable on long timescales is exceeded. We present a simplified model of rain water infiltration in the snow coupled to a transient permafrost model. While small amounts of rain have only minor impact on the ground surface temperature, strong rain events have a long-lasting impact. We show that consecutively applying the conditions encountered in the winter season 2005/2006 results in the formation of an unfrozen zone in the soil after three to five years, depending on the prescribed soil properties. If water infiltration in the snow is disabled in the model, more time is required for the permafrost to reach a similar state of degradation.

Fate of urea nitrogen applied to a banana crop in the wet tropics of Queensland

This paper reports a study in the wet tropics of Queensland on the fate of urea applied to a dry or wet soil surface under banana plants. The transformations of urea were followed in cylindrical microplots (10.3 cm diameter × 23 cm long), a nitrogen (N) balance was conducted in macroplots (3.85 m × 2.0 m) with 15N labelled urea, and ammonia volatilization was determined with a mass balance micrometeorological method. Most of the urea was hydrolysed within 4 days irrespective of whether the urea was applied onto dry or wet soil. The nitrification rate was slow at the beginning when the soil was dry, but increased greatly after small amounts of rain; in the 9 days after rain 20% of the N applied was converted to nitrate. In the 40 days between urea application and harvesting, the macroplots the banana plants absorbed only 15% of the applied N; at harvest the largest amounts were found in the leaves (3.4%), pseudostem (3.3%) and fruit (2.8%). Only 1% of the applied N was present in the roots. Sixty percent of the applied N was recovered in the soil and 25% was lost from the plant-soil system by either ammonia volatilization, leaching or denitrification. Direct measurements of ammonia volatilization showed that when urea was applied to dry soil, and only small amounts of rain were received, little ammonia was lost (3.2% of applied N). In contrast, when urea was applied onto wet soil, urea hydrolysis occurred immediately, ammonia was volatilized on day zero, and 17.2% of the applied N was lost by the ninth day after that application. In the latter study, although rain fell every day, the extensive canopy of banana plants reduced the rainfall reaching the fertilized area under the bananas to less than half. Thus even though 90 mm of rain fell during the volatilization study, the fertilized area did not receive sufficient water to wash the urea into the soil and prevent ammonia loss. Losses by leaching and denitrification combined amounted to 5% of the applied N.

Drought tolerance of the dehydrated root of Schismus arabicus seedlings and regrowth after rehydration, affected by caryopsis size and duration of dehydration

The unique drought tolerance of the single root of Schismus arabicus seedlings was compared with the roots of barley subjected to the same drought conditions. S. arabicus seedlings with roots and coleoptiles that were 1 to 2 mm or longer continued to grow and develop into normal plants when rehydrated after various dry periods. Moreover, seedlings originating from larger caryopses grew faster than those from small caryopses. When seedlings of cultivated barley Noga were dehydrated under the same conditions, none of the roots survived even after one day of drought. However, the barley seedlings survived because coleoptile growth was re-initiated following rehydration and new adventitious roots developed. S. arabicus is one of the very common annual plant species in large areas in theextreme deserts of the SaharoArabian phytogeographic region where the low rainfall and its distribution in winter are unpredictable. The ability of small portions of the S. arabicus soil seed bank to germinate after small amounts of rain, together with seedling drought tolerance for at least 29 days, may increase the chance of survival of this plant species. Seedlings originating from larger caryopses have even a higher chance of survival.

Regionalization and spatial properties of Ceará State rainfall in northeast Brazil

The overall daily rainfall pattern of Ceará for 19 years, 1974–1992, was analyzed in terms of physiography and atmospheric circulation. This information was used to suggest a regionalization of the state's rainfall into homogeneous areas. The three large‐scale precipitation mechanisms (Intertropical Convergence Zone, cold fronts, and upper air vortices) interact and create a certain rainfall pattern over the state during different months. An example of this interaction is the opposite behavior that the northern and southern parts of the state tend to have when considering the amount of precipitation during the rainy season; That is, in general, large amounts of rain in the southern part of the state tend to be associated with small amounts of rain in the northern part and vice versa, as influenced by the opposite influence of the cold fronts and the upper air vortices. At the same time, the orographical influence enhances the precipitation in the northern part of the state and decreases precipitation in the central part of the state. The state could be divided into six homogeneous precipitation regions: (1) the northwestern part of the state, locally influenced by the mountain massif of Serra da Ibiapaba; (2)–(3) the northern and northeastern Ceará influenced locally by sea breeze and the slopes of the Serra de Baturité; (4)–(5) the central state, influenced by the Chapada do Apodi and the Serra de Uruburetama; and (6) the southern part of the state, influenced mostly by cold fronts and by the slopes of the Serra do Araripe.

Characterization of raindrop size distributions at the Vale Formoso Experimental Erosion Center

Previous studies carried out by the authors and other references collected from the literature have shown the inadequacy of most rainfall erosivity indexes and specially the Wischmeier rainfall erosivity index, for properly estimating erosivity in southern Portugal and in Mediterranean climates. In order to measure raindrop size distributions of natural rainfall automatically and continuously, a device was installed at the Vale Formoso Experimental Erosion Center. The main objective was to correlate field measurements to model estimates. The relatively small amounts of rain which fell at the station last year meant that it was only possible to check the calibration of the device; preliminary results are presented here. Classical raindrop distributions are compared with the data and relationships between rainfall intensity and kinetic energy of rainfall are obtained and compared with that proposed by RUSLE.

Recent Rainfall Trends in Africa, the Middle East and India

IN the Middle East and Africa north of the Sahara the wet season extends from October to May; small amounts of rain also fall in Pakistan and north-west India at that time of year. Winter–spring rainfall in these areas is controlled primarily by divergence patterns in pressure troughs in the mid- and upper-tropospheric circumpolar westerlies. Rainfall is associated with the widespread ascent of warm, moist air from the tropics on the eastern side of the troughs, and also with deep convective instability in the cold air at, and slightly to the rear of, the trough axes, especially over coasts and mountains. It is in winter that the increase in the latitudinal temperature gradient in the northern hemisphere causes the westerly circulation to increase in strength and the westerly troughs to penetrate into sub-tropical latitudes. In summer, the latitudinal temperature gradient is at a minimum, the general circulation is relatively weak, and the westerly troughs are of small amplitude and restricted to middle and high latitudes.

The Past Summer

BROADLY speaking, the past summer was essentially dry, generally cool, and particularly sunless considering the small amount of rain.