Periods Of Intense Rainfall Research Articles

Brood Reduction by Infanticide in Peregrine Falcons

This note describes an observation of infanticide in the Peregrine Falcon (Falco peregrinus tundrius). During the summer of 2011, a marked adult female and an unmarked adult male produced and hatched two eggs at a known and regularly monitored nest site. Motion-sensitive camera images indicated that the adults attended to the two nestlings and fed them in a manner that resulted in growth and development typical for the nestlings produced in the study population. During a period of intense rainfall, the two nestlings were left unattended for several hours; both nestlings were clearly distressed, and one was close to death. When the visibly wet marked adult female returned to the nest ledge, she killed and partially consumed the smaller and weaker of the two nestlings. The female flew from the nest ledge without feeding the remaining nestling and returned shortly afterward to kill and partially consume the second nestling. This is the first documentation of infanticide in wild Peregrine Falcons.

Using building simulation to model the drying of flooded building archetypes

With a changing climate, London is expected to experience more frequent periods of intense rainfall and tidal surges, leading to an increase in the risk of flooding. This paper describes the simulation of the drying of flooded building archetypes representative of the London building stock using the EnergyPlus-based hygrothermal tool ‘University College London-Heat and Moisture Transfer (UCL-HAMT)’ in order to determine the relative drying rates of different built forms and envelope designs. Three different internal drying scenarios, representative of conditions where no professional remediation equipment is used, are simulated. A mould model is used to predict the duration of mould growth risk following a flood on the internal surfaces of the different building types. Heating properties while keeping windows open dried dwellings fastest, while purpose built flats and buildings with insulated cavity walls were found to dry slowest.

DInSAR analysis of ALOS PALSAR images for the assessment of very slow landslides: the Tena Valley case study

In this work we analyse the performance of advanced land observing satellite (ALOS) phased array type L-band syntetic aperture radar (PALSAR) images for mapping and monitoring of very slow landslides using conventional differential interferometry in the Tena Valley (Central Pyrenees, Spain). These results are compared with those retrieved in previous works where multi-band advanced differential interferometric synthetic aperture radar (DInSAR) analysis was performed for the same area using PSI techniques. The study area is largely underlain by slates (ca. 80 %) where large deep-seated very slow earth flows are dominant. The results reveal that DInSAR analysis is able to measure displacements of landslides with a greater spatial coverage than PSI analysis, but for a lower amount of them (nine against 51). Overall, the combination of the DInSAR and multi-band PSI analysis permitted to map and monitor 68 % of the landslides in Tena Valley. From this amount, 63 landslides are considered as active. The main advantage of DInSAR with respect to PSI analysis is the capability to detect faster movements (up to 145 cm year−1) derived from the 46 days interferograms. That is the case of Sextas and La Selva landslides where an acceleration of the moving mass was measured after intense rainfall periods producing major damages to linear infrastructures. The combination of measured displacement from ALOS interferograms, with the observed damages on the A-136 road, was useful to assess the potential damage that could cause these slow movements. In general, it is demonstrated that even though PSI analysis provides a better performance in terms of landslide mapping, L-band DInSAR analysis provides an added value for landslide hazard assessment through radar remote sensing. For this reason it is necessary to encourage the launch of new satellite missions similar to ALOS PALSAR that could operate with shorter revisiting time periods.

Is reactivation of toxoplasmic retinochoroiditis associated to increased annual rainfall?

Background: Reactivation of toxoplasmic retinochoroiditis is the most frequent form of uveitis in Misiones, Argentina. Fluctuations in the number of patients consulting with this type of uveitis were detected during the last decade. Since the province was consecutively exposed to rainy and dry periods over the last years, we decided to explore whether a relationship between reactivation of toxoplasmic retinochoroiditis and rain might be established according to the data registered during the 2004–2010 period. Results: The frequency of toxoplasmic reactivation episodes increases when precipitation increases (mostly in second and fourth trimesters of each year). Analysis of the independent variables demonstrates that precipitation is a significant predictor of the frequency of reactivation episodes. Although registered toxoplasmic reactivations were more frequent during the third trimester of the year, the association between the third trimester and the reactivation episodes did not reach statistical significance. Conclusion: Prolonged and intense rainfall periods were significantly associated with the reactivation of toxoplasmic retinochoroiditis. Changes promoted by this climatic condition on both the parasite survival in the soil as well as a putative effect on the host immune response due to other comorbidities are discussed.

Predicting the microbial exposure risks in urban floods using GIS, building simulation, and microbial models

London is expected to experience more frequent periods of intense rainfall and tidal surges, leading to an increase in the risk of flooding. Damp and flooded dwellings can support microbial growth, including mould, bacteria, and protozoa, as well as persistence of flood-borne microorganisms. The amount of time flooded dwellings remain damp will depend on the duration and height of the flood, the contents of the flood water, the drying conditions, and the building construction, leading to particular properties and property types being prone to lingering damp and human pathogen growth or persistence. The impact of flooding on buildings can be simulated using Heat Air and Moisture (HAM) models of varying complexity in order to understand how water can be absorbed and dry out of the building structure. This paper describes the simulation of the drying of building archetypes representative of the English building stock using the EnergyPlus based tool ‘UCL-HAMT’ in order to determine the drying rates of different abandoned structures flooded to different heights and during different seasons. The results are mapped out using GIS in order to estimate the spatial risk across London in terms of comparative flood vulnerability, as well as for specific flood events. Areas of South and East London were found to be particularly vulnerable to long-term microbial exposure following major flood events.

Cases distribution of leptospirosis in City of Manaus, State of Amazonas, Brazil, 2000-2010

Leptospirosis is an infectious disease caused by microorganisms of the genus Leptospira that affects several species of animals, including the human beings. The study described the confirmed cases of leptospirosis in Manaus, from 2000 to 2010. A descriptive study based on secondary data analysis of Secretaria Municipal de Saúde (SEMSA), Sistema de Informação de Agravos de Notificação SINAN and Sistema de Informação sobre Mortalidade (SIM) analyzing the variables: age group, gender, clinical aspects and geographic area and lethality. Were reported 665 cases of leptospirosis, 339 were confirmed and 35 (10.3%) died. The largest number of cases occurred in May (16.8%), March (13.3%) and April (11.4%), a period of intense rainfall. The city areas with the greatest occurrence of the disease were South (26.6%), West (23.5%) and East (19.7%), areas of the greatest precariousness socio-environment. The largest number of cases, including deaths, occurred in the age group from 14 to 44.9 years (74%), being that 291 (85.8%) were male and 48 (14.1%) females. The most frequent symptoms were fever, myalgia, headache and jaundice. In relation to the social conditions were identified low education, poor housing, absence of sanitation and low income. In Manaus, despite the implementation of the Social and Environmental Program of Igarapés of Manaus (PROSAMIM), there are still areas that need a proper urbanization and improvements in socio-environmental conditions, reducing the level of exposure of the human beings that living in these locations.

Towards hydrological triggering mechanisms of large deep-seated landslides

It is a widely accepted idea that hydrologically triggered deep-seated landslides are initiated by an increase in pore-water pressure on potential slip surface induced by rising groundwater level after prolonged period of intense rainfall although the process is not fully understood. In order to contribute to better understanding, the rainfall–groundwater relationships, hydrogeological monitoring and repeated geoelectrical imaging were carried out from March 2007 to April 2011 in large deep-seated landslide near Ľubietova (Western Carpathians) catastrophically reactivated at the end of February 1977. Based on our observations, groundwater level (GWL) response to precipitation differs considerably with respect to both overall hydrological conditions and GWL mean depth. While the rate of GWL increase up to 25 cm/day were measured after some rainfall events during wet periods, noticeably lower recharge rate (up to 1–2 cm/day) and delayed GWL response to rainfall (usually from 2 weeks to 2–4 months) were observed at the beginning of the wet season after considerable depression of GWLs due to previous effective rainfall deficit. Likewise, slow GWL fluctuations without short-term oscillations are typical for deeper GWLs. Thus, long-term (several seasons to several years) hydrological conditions affect markedly groundwater response to rainfall events in the studied landslide and can be crucial for its behaviour. Comparison of hydrological conditions characterising the analysed period with those that accompanied the landslide reactivation in 1977 allow us to assume that slightly above-average rainy season following the prolonged wet period can be far more responsible for movement acceleration (and possibly failure initiation) in deep landslides than the isolated season of extreme precipitation following a longer dry period. This is true especially for landslides in regions with significant seasonal temperature changes where potential effective precipitation (PEP), calculated as excess of precipitation (P) over potential evapotranspiration (PET), may be efficiently used for estimation of slope saturation condition.

Palaeoprecipitation record using O-isotope studies of the Himalayan Foreland Basin sediments, NW India

The Himalayan foreland basin sediments were deposited during a crucial time period in the Himalayan orogeny. This period, in the Tertiary, has become major focus of research because of the large scale uplift of the Himalayan range which has greatly modified the climate of the Asian continent. The present South Asian monsoonal climate is believed to be a consequence of Himalayan uplift during this period. Also the Himalayan orogeny comprises a major regional tectonic event of the Earth. Hence, the study of these Himalayan foreland basin sediments are not only significant in revealing the palaeoclimatic history of the Asian continent but also paves a way for understanding of the effects of Himalayan orogeny on global climate. Here we report a palaeoprecipitation history of the Ramnagar sub-basin since Miocene times and its regional correlation to other sub-basins of the Himalayan mountain belt. An attempt has been made to use oxygen isotope ratios of pedogenic carbonates in Siwalik palaeosols as proxy palaeo-recorders to deduce the palaeoclimatic history of the Jammu region in the Ramnagar sub-basin for the first time.A total of 141 pedogenic carbonates have been analyzed from three Siwalik sections covering a lateral stretch of approximately 40-50Km along strike. The δ18O values vary from −12.31‰ to −5.89‰ and, when plotted against age, indicate that δ18O values, on average, become ~2‰ enriched from the oldest to the youngest analyzed sediments except for largely depleted δ18O values around 10Ma, 5Ma and 1.8Ma. This ~2‰ increase in calculated δ18O values could have been possible by an ~3°C increase in mean annual air temperature; conversely the largely negative δ18O values indicate periods of intense rainfall or stronger monsoonal conditions. An increase of 2.6‰ in δ18O values has been found from the 10Ma rainfall event to that at 1.8Ma which indicates a reduction of ~173mm in rainfall intensity and amount. Hence, precipitation reconstructions indicate a progressive increase in aridity from ~12Ma to Recent excluding a short term increases in rainfall or monsoon intensity at around 10Ma, 5Ma and 1.8Ma.This pattern of palaeoprecipitation change is similar to the changes documented in other sub-basins of the Himalayan mountain range. Further, monsoon intensification at around 10Ma, 5Ma and 1.8Ma is also observable in various other proxy records, thereby suggesting the role of significant regional tectonism in the evolution and intensification of the present South Asian monsoon climate. Our results indicate that from the Mid-Miocene to Recent, except for the periods of largely depleted δ18O values, the average δ18O value increased by ~2‰. The general increase in average δ18O values from Lower to Upper Siwalik sediments can be explained by changes in both continentality and latitude of the moisture source. It seems likely that this long term increase in δ18O values was due to the uplift of the Himalayas and the Tibetan Plateau in the north which acted as a barrier to the passage of airmasses from Central Asia in the north, thereupon with time restricting the source of airmasses to the south from the Indian Ocean.

Spatio-temporal analysis of extreme precipitation regimes across South Korea and its application to regionalization

Assessing spatio-temporal variability of extreme rainfall is required to establish future plans and policies for water resource management. One of the main objectives of this study is to introduce an effective approach based on circular statistics for assessing the seasonality of the extreme precipitation. Circular statistics explicitly reflect the seasonal pattern of precipitation with maximum frequency of the timing of daily and monthly maximums. In southern Korea, a dominant frequency was identified in early July. The timing of the monthly maximum has been delayed in northern Korea. In the case of the daily maximum, the end of June is the period of most intense rainfall, with the exception of the east coast near Gangrung. A long-term temporal variation of timed monthly and daily maximums was investigated by a 30-year moving average for main stations. Monthly peak times of Seoul and Gangrung continuously moved backward while monthly peak times of Mokpo and Busan has moved forward since the 1960’s. These features could be influenced by inherent variations in the East Asian monsoon system. Given the identified spatio-temporal pattern, this study was extended to characterize regional patterns of extreme rainfall over Korea. A new concept in regionalization procedures was developed on the basis of existing approaches that mainly utilize simple moments of data. In this study, the K-means method was incorporated with the temporal pattern of the extreme rainfalls in order to better characterize hydrologic patterns for regional frequency analysis. The results showed that the proposed approach is promising for the region in term improving the physical understanding of extreme rainfall.

Haematite in Lateritic Soils Aids Groundwater Disinfection

Microbiologically contaminated water severely impacts public health in low-income countries, where treated water supplies are often inaccessible to much of the population. Groundwater represents a water source that commonly has better microbiological quality than surface water. A 2-month intensive flow and quality monitoring programme of a spring in a densely settled, unsewered parish of Kampala, Uganda, revealed the persistent presence of high chloride and nitrate concentrations that reflect intense loading of sewage in the spring’s catchment. Conversely, thermotolerant coliform bacteria counts in spring water samples remained very low outside of periods of intense rainfall. Laboratory investigations of mechanisms responsible for this behavior, achieved by injecting a pulse of H40/1 bacteriophage tracer into a column packed with locally derived granular laterite, resulted in near-total tracer adsorption. X-ray diffraction (XRD) analysis showed the laterite to consist predominantly of quartz and kaolinite, with minor amounts (<5%) of haematite. Batch studies comparing laterite adsorption capacity with a soil having comparable mineralogy, but with amorphous iron oxide rather than haematite, showed the laterite to have a significantly greater capacity to adsorb bacteriophage. Batch study results using pure haematite confirmed that its occurrence in laterite contributes substantially to micro-organism attenuation observed and serves to protect underlying groundwater.

Relating the X-band opacity of a tropical tree canopy to sapflow, rain interception and dew formation

During summer and autumn 2007, a 11 GHz microwave radiometer was deployed in an experimental tree plantation in Sardinilla, Panama. The opacity of the tree canopy was derived from incoming brightness temperatures received on the ground. A collocated eddy-covariance flux tower measured water vapor fluxes and meteorological variables above the canopy. In addition, xylem sapflow of trees was measured within the flux tower footprint. We observed considerable diurnal differences between measured canopy opacities and modeled theoretical opacities that were closely linked to xylem sapflow. It is speculated that dielectric changes in the leaves induced by the sapflow are causing the observed diurnal changes. In addition, canopy intercepted rain and dew formation also modulated the diurnal opacity cycle. With an enhanced canopy opacity model accounting for water deposited on the leaves, we quantified the influence of canopy stored water (i.e. intercepted water and dew) on the opacity. A time series of dew formation and rain interception was directly monitored during a period of two weeks. We found that during light rainfall up to 60% of the rain amount is intercepted by the canopy whereas during periods of intense rainfall only 4% were intercepted. On average, 0.17 mm of dew was formed during the night. Dew evaporation contributed 5% to the total water vapor flux measured above the canopy.

Irish peat slides 2006–2010

The purpose of this paper is to present a review of peat landslide events in Ireland since 2003, when two significant events occurred. Since 2003, there have been at least 13 such events. Several of these events included more than one slide. It is also likely that there have been unrecorded slides. It seems that there is an increasing incidence of such events, but they seem to occur in clusters with intervening quiet periods. These clusters coincide with periods of intense rainfall. For many slides, at least two causal factors can be identified. Primarily these comprised intense rainfall but human activities such as road construction and peat cutting also contributed to the slides. Detailed geotechnical testing of the peat, including laboratory direct simple shear tests (DSS), is reported for two of the slides. Back-analysis of these two failures suggests that the mobilised strength of the material in the failure surface is similar to that measured in the DSS tests. However, conventional geotechnical analyses need to be treated with caution as they fail to account for the complex interactions in the sliding surface and in particular the lubricating role of water.

C6 Slope and Road Drainage

Good drainage is a key element in the satisfactory functioning of all roads. In hilly and mountainous areas especially, drainage management is critical to the performance and stability of a road and its structures. Within very short periods of time intense rainfall can lead to landslides and extensive erosion on slopes, while sediment-laden storm runoff can cause blockage to drainage structures and scour of foundations and fill slopes. The control of surface water must therefore be uppermost in the minds of those responsible for the design, construction and maintenance of mountain roads. Slope drainage can be applied both as a routine precautionary measure to improve stability and reduce the incidence of landslides and erosion, and as a reactionary measure to assist in the stabilization of slopes that have already failed. Figures C6.1 and C6.2 and Table C6.1 outline the typical methods of slope drainage found on mountain roads. As a general point, it is recommended that every opportunity is taken to improve the natural drainage of slopes adjacent to roads. This should normally include: Fig. C6.1. Typical slope drainage measures. Fig. C6.2. Typical slope drainage details. View this table: Table C6.1. Types of slope drainage, their function and limitations In order to maximize the efficiency of surface drainage the following guidelines are recommended: ### C6.2.1 Routine slope drainage The main function of drainage in this context is to control surface runoff. A drainage ‘cut-off’ or catch-water drain is the …

A comparison of gauge and radar precipitation data for simulating an extreme hydrological event in the Severn Uplands, UK

AbstractThis paper provides a comparison of gauge and radar precipitation data sources during an extreme hydrological event. November–December 2006 was selected as a time period of intense rainfall and large river flows for the Severn Uplands, an upland catchment in the United Kingdom. A comparison between gauge and radar precipitation time‐series records for the event indicated discrepancies between data sources, particularly in areas of higher elevation. The HEC‐HMS rainfall‐runoff model was selected to assess the accuracy of the precipitation to simulate river flows for the extreme event. Gauge, radar and gauge‐corrected radar rainfall were used as model inputs. Universal cokriging was used to geostatistically interpolate gauge data with radar and elevation data as covariates. This interpolated layer was used to calculate the mean‐field bias and correct the radar composites. Results indicated that gauge‐ and gauge‐corrected radar‐driven models replicated flows adequately for the extreme event. Gauge‐corrected flow predictions produced an increase in flow prediction accuracy when compared with the raw radar, yet predictions were comparative in accuracy to those using the interpolated gauge network. Subsequent investigations suggested this was due to an adequate spatial and temporal resolution of the precipitation gauge network within the Severn Uplands. Results suggested that the six rain gauges could adequately represent precipitation variability of the Severn Uplands to predict flows at an approximately equal accuracy to that obtained by radar. Temporally, radar produced an increase in flow prediction accuracy in mountainous reaches once the gauge time step was in excessive of an hourly interval. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Flood-producing cloud bands over the Kalahari Desert

The characteristics of flood-producing cloud bands over the Kalahari Desert (15-30°S, 15-22°E) are described using daily time-scale observations, reanalysis and satellite data. The cloud band extends southward from Angola, producing short periods of intense rainfall over Namibia. Their frequency of occurrence is ∼8% according to singular value decomposition of gridded 1° daily GPCP rainfall 1996-2008. The environmental features evident from case study and composite analysis include: (1) cut-off low over the Namibian coast and deep anticyclonic ridge south of Africa, (2) inflow of air from vegetated surfaces to the northeast (Q > 300 W m−2) into a 300 km wide meridional axis, (3) a large-scale sea breeze that enhances afternoon convection, and in the background, (4) warming of the southeast Atlantic Ocean off Angola. Short-range GFS forecasts appear accurate for the devastating 5 February 2009 event 5 days in advance.

The influence of multiple environmental stressors on the limpet Cellana toreuma during the summer monsoon season in Hong Kong

Although environmental stressors affect natural systems in a multitude of ways, the interactive effect of multiple stressors on ecological assemblages remains largely misunderstudied. On tropical shores which experience seasonal monsoons, rocky intertidal habitats are physiologically stressful environments, being strongly affected by high temperatures and monsoon rains during emersion. In Hong Kong the limpet, Cellana toreuma, often takes refuge in mid-shore tidepools. In summer, these populations experience high mortality, probably as a result of stressful environmental conditions during low-spring tide days with high temperatures and/or intense rainfall periods can occur. Laboratory experiments were designed to mimic the effects of temperature stress (and increasing pool salinity) and reduced salinity as a result of monsoon rains on C. toreuma in tidepools . In general, haemolymph osmolality increased with salinity and limpet mortality increased with temperature. As salinity decreased after simulated rainfall, haemolymph osmolality (after 60 min) and survival (after 180 min) were significantly lower than in control treatments. Salinity fluctuations, coupled with high temperatures during emersion had both sub-lethal physiological effects and lethal effects on limpets in tidepools. Conducting experiments of multiple stressors simultaneously, however, revealed no interaction between hot temperatures and salinity variation, both of which operated independently for different response variables. Individually, therefore, hot temperatures and large salinity changes associated with the wet monsoon season are likely to play an important role in the population dynamics of intertidal species such as C. toreuma, and as a result will influence the structure and functioning of tropical rocky shores.

Understanding Causes and Impacts of the Dinoflagellate, Cochlodinium polykrikoides, Blooms in the Chesapeake Bay

During August and September 2007, the lower Chesapeake Bay and its tributaries experienced a massive bloom of Cochlodinium polykrikoides Margalef (>104 cells per milliliter) that persisted for over a month, was extremely patchy, and at times penetrated into the Atlantic Ocean. The onset of the bloom coincided with a period of intense rainfall and stormwater runoff after a protracted summer drought period. Genetic evidence showed this species to be distinct from many Asian strains but similar to other North American strains. Populations dominated by C. polykrikoides took up a variety of nitrogenous compounds to support their growth and were able to mobilize additional sources of organic nutrients through peptide hydrolysis. Bioassays determined that C. polykrikoides exerted a lethal affect on juvenile fish and shellfish, causing 100% mortality of juvenile fish (Cyprinodon variegates) in less than 24 h and 20% mortality in juvenile American oysters (~21 mm; Crassostrea virginica) within 72 h.

High Temporal Resolution Monitoring of Multiple Pollutant Responses in Drainage from an Intensively Managed Grassland Catchment Caused by a Summer Storm

This work presents data on a suite of diffuse pollutants, monitored in a stream draining an intensively managed grassland on a 30 min time step during a period of intense rainfall to better understand their sources and pathways. Nitrite (92 μg l−1), particulate phosphorus (107 μg l−1) and soluble phosphorus (74 μg l−1) exceeded environmental limits during base flow. Concentrations of nitrate and nitrite were decreased during the storm event, whereas all other pollutants generally increased and exceeded environmental limits where specified, especially when associated with a small subsidiary hydrograph on the rising limb of the main hydrograph. Total pollutants loads, when using a 60 min sampling frequency, would have led to significant over and under-estimations depending on which 60 min sample set was used. In the worst case, loads of ammonium could have been under-estimated by 35% or over estimated by 25% with errors being associated with loads on the rising limb of the hydrograph and more specifically a small subsidiary hydrograph. This subsidiary hydrograph may have occurred as a result of runoff from the farm hard standings within the catchment. Incidental transfer of pollutants associate with this runoff have masked the overall grassland pollutant response. To better understand these different source areas and pollutant dynamics, there is a need for novel tracing techniques to elucidate their relative contribution and pathways.

The Influence of Irrigation on Slope Movements, Ventura County, California, USA

Ancient landslides at two locations in Ventura County, California, USA, that have morphology consistent with thousands of years of stability were reactivated in 1988 and 1992–1994. The timing of reactivation was assisted by the burial or destruction of oil wells that penetrated through the landslides and had operated continuously since at least 1948. Slope movement at Grimes Canyon began during a period of lower-than-normal rainfall (compared to average precipitation since 1948), which suggests that irrigation triggered instability. At South Mountain, landsliding initiation overlapped a period of intense rainfall; however, the influence of irrigation, which may have contributed antecedent groundwater conditions conducive to slope failure, may not be ruled out. These case studies illustrate the complexity of identifying landslide triggering mechanisms, and they show that triggering of deep-seated landslides may be aided by climatic conditions or irrigation.

The Impact of Cumulus Suppression on the Baiu Front Simulated by an AGCM

This paper discusses the effect of cumulus suppression (CS), applied in the Arakawa-Schubert (AS) cumulus parameterization, on the Baiu front simulated with an atmospheric general circulation model (AGCM; T106L56: horizontal resolution ~1.1°, 56 vertical layers). As an additional condition of the AS cumulus parameterization, CS permitted cumulus convection only when the environmental relative humidity averaged in the modeled cumulus cloud of the AS scheme exceeded 80%. To evaluate the effect of CS, the results of simulations with CS (CS run) are compared with those without CS (NOCS run). Detailed analysis was carried out for June, because the Baiu front in the real atmosphere is usually sustained quasi-steadily during June. Whereas the distribution and amount of 5-year June mean Baiu precipitation in the CS run was generally similar to that in the NOCS run, the standard deviation of daily precipitation of 5-year June in the CS run was significantly larger than that in the NOCS runs. The CS condition increased heavy rainfall and temporal variation of Baiu precipitation. The CS run also suppressed precipitation in the southern area of the Baiu front, as seen in observations. Examination of the Baiu front during intense-rainfall periods in the model showed that characteristics of the Baiu front and frontal disturbances were reasonably simulated, in some years, by both the CS and NOCS runs, to a certain extent. However, the CS condition improved the occurrence of intense rainfall events at the Baiu front, and the reproduction of the Baiu frontal disturbances. Both of these features became closer to actual observed features.