Total Amount Of Precipitation Research Articles

Evaluation of modern and mid-Holocene seasonal precipitation of the Mediterranean and northern Africa in the CMIP5 simulations

Abstract. We analyse the spatial expression of seasonal climates of the Mediterranean and northern Africa in pre-industrial (piControl) and mid-Holocene (midHolocene, 6 yr BP) simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Modern observations show four distinct precipitation regimes characterized by differences in the seasonal distribution and total amount of precipitation: an equatorial band characterized by a double peak in rainfall, the monsoon zone characterized by summer rainfall, the desert characterized by low seasonality and total precipitation, and the Mediterranean zone characterized by summer drought. Most models correctly simulate the position of the Mediterranean and the equatorial climates in the piControl simulations, but overestimate the extent of monsoon influence and underestimate the extent of desert. However, most models fail to reproduce the amount of precipitation in each zone. Model biases in the simulated magnitude of precipitation are unrelated to whether the models reproduce the correct spatial patterns of each regime. In the midHolocene, the models simulate a reduction in winter rainfall in the equatorial zone, and a northward expansion of the monsoon with a significant increase in summer and autumn rainfall. Precipitation is slightly increased in the desert, mainly in summer and autumn, with northward expansion of the monsoon. Changes in the Mediterranean are small, although there is an increase in spring precipitation consistent with palaeo-observations of increased growing-season rainfall. Comparison with reconstructions shows most models underestimate the mid-Holocene changes in annual precipitation, except in the equatorial zone. Biases in the piControl have only a limited influence on midHolocene anomalies in ocean–atmosphere models; carbon-cycle models show no relationship between piControl bias and midHolocene anomalies. Biases in the prediction of the midHolocene monsoon expansion are unrelated to how well the models simulate changes in Mediterranean climate.

Evaluation of CMIP5 continental precipitation simulations relative to satellite-based gauge-adjusted observations

Numerous studies have emphasized that climate simulations are subject to various biases and uncertainties. The objective of this study is to cross-validate 34 Coupled Model Intercomparison Project Phase 5 (CMIP5) historical simulations of precipitation against the Global Precipitation Climatology Project (GPCP) data, quantifying model pattern discrepancies and biases for both entire data distributions and their upper tails. The results of the Volumetric Hit Index (VHI) analysis of the total monthly precipitation amounts show that most CMIP5 simulations are in good agreement with GPCP patterns in many areas, but that their replication of observed precipitation over arid regions and certain sub-continental regions (e.g., northern Eurasia, eastern Russia, central Australia) is problematical. Overall, the VHI of the multi-model ensemble mean and median also are superior to that of the individual CMIP5 models. However, at high quantiles of reference data (e.g., the 75th and 90th percentiles), all climate models display low skill in simulating precipitation, except over North America, the Amazon, and central Africa. Analyses of total bias (B) in CMIP5 simulations reveal that most models overestimate precipitation over regions of complex topography (e.g. western North and South America and southern Africa and Asia), while underestimating it over arid regions. Also, while mostmore » climate model simulations show low biases over Europe, inter-model variations in bias over Australia and Amazonia are considerable. The Quantile Bias (QB) analyses indicate that CMIP5 simulations are even more biased at high quantiles of precipitation. Lastly, we found that a simple mean-field bias removal improves the overall B and VHI values, but does not make a significant improvement in these model performance metrics at high quantiles of precipitation.« less

Variability of extreme precipitation over Europe and its relationships with teleconnection patterns

Abstract. A growing interest in extreme precipitation has spread through the scientific community due to the effects of global climate change on the hydrological cycle, and their threat to natural systems' higher than average climatic values. Understanding the variability of precipitation indices and their association to atmospheric processes could help to project the frequency and severity of extremes. This paper evaluates the trend of three precipitation extremes: the number of consecutive dry/wet days (CDD/CWD) and the quotient of the precipitation in days where daily precipitation exceeds the 95th percentile of the reference period and the total amount of precipitation (or contribution of very wet days, R95pTOT). The aim of this study is twofold. First, extreme indicators are compared against accumulated precipitation (RR) over Europe in terms of trends using non-parametric approaches. Second, we analyse the geographically opposite trends found over different parts of Europe by considering their relationships with large-scale processes, using different teleconnection patterns. The study is accomplished for the four seasons using the gridded E-OBS data set developed within the EU ENSEMBLES project. Different patterns of variability were found for CWD and CDD in winter and summer, with north–south and east–west configurations, respectively. We consider physical factors in order to understand the extremes' variability by linking large-scale processes and precipitation extremes. Opposite associations with the North Atlantic Oscillation in winter and summer, and the relationships with the Scandinavian and East Atlantic patterns as well as El Niño/Southern Oscillation events in spring and autumn gave insight into the trend differences. Significant relationships were found between the Atlantic Multidecadal Oscillation and R95pTOT during the whole year. The largest extreme anomalies were analysed by composite maps using atmospheric variables and sea surface temperature. The association of extreme precipitation indices and large-scale variables found in this work could pave the way for new possibilities regarding the projection of extremes in downscaling techniques.

The atmospheric component of the Mediterranean Sea water budget in a WRF multi-physics ensemble and observations

The use of high resolution atmosphere–ocean coupled regional climate models to study possible future climate changes in the Mediterranean Sea requires an accurate simulation of the atmospheric component of the water budget (i.e., evaporation, precipitation and runoff). A specific configuration of the version 3.1 of the weather research and forecasting (WRF) regional climate model was shown to systematically overestimate the Mediterranean Sea water budget mainly due to an excess of evaporation (~1,450 mm yr−1) compared with observed estimations (~1,150 mm yr−1). In this article, a 70-member multi-physics ensemble is used to try to understand the relative importance of various sub-grid scale processes in the Mediterranean Sea water budget and to evaluate its representation by comparing simulated results with observed-based estimates. The physics ensemble was constructed by performing 70 1-year long simulations using version 3.3 of the WRF model by combining six cumulus, four surface/planetary boundary layer and three radiation schemes. Results show that evaporation variability across the multi-physics ensemble (∼10 % of the mean evaporation) is dominated by the choice of the surface layer scheme that explains more than ∼70 % of the total variance and that the overestimation of evaporation in WRF simulations is generally related with an overestimation of surface exchange coefficients due to too large values of the surface roughness parameter and/or the simulation of too unstable surface conditions. Although the influence of radiation schemes on evaporation variability is small (∼13 % of the total variance), radiation schemes strongly influence exchange coefficients and vertical humidity gradients near the surface due to modifications of temperature lapse rates. The precipitation variability across the physics ensemble (∼35 % of the mean precipitation) is dominated by the choice of both cumulus (∼55 % of the total variance) and planetary boundary layer (∼32 % of the total variance) schemes with a strong regional dependence. Most members of the ensemble underestimate total precipitation amounts with biases as large as 250 mm yr−1 over the whole Mediterranean Sea compared with ERA Interim reanalysis mainly due to an underestimation of the number of wet days. The larger number of dry days in simulations is associated with a deficit in the activation of cumulus schemes. Both radiation and planetary boundary layer schemes influence precipitation through modifications on the available water vapor in the boundary layer generally tied with changes in evaporation.

Stochastic simulation of daily precipitation: A copula approach

Abstract The traditional methods of simulating daily precipitation have paid little attentionto the inherent dependence structure between the total precipitation amount and theprecipitation frequency for a xed period of time. To address this issue, we proposea new simulation algorithm using copula in order to incorporate the dependence intothe traditional methods. The algorithm consists of two parts: First, while reecting theobserved dependence, we generate the total precipitation amount (S) and the frequency(N) during the period of interest; then we simulate the daily precipitation whose ag-gregation matches the pair of (N;S) generated in the rst part. Our result shows thatthe proposed method substantially improves the traditional methods.Keywords: Copula, daily precipitation simulation, gamma distribution, Markov chain. 1. Introduction Simulating daily precipitation data is an important task with a wide range of applications,e.g., agriculture (Sharpley and Williamson, 1990a, 1990b), ecology (Kittel et al., 1995),hydrological systems (Pickering et al., 1988) and nance (Leobacher and Ngare, 2011).Traditionally, the simulation has been governed by two independent stochastic models; onefor precipitation occurrence and the other for daily precipitation amount. For the former,the Markov chain models have been used extensively and, for the latter, various stochasticmodels such as exponential, gamma, skewed normal and mixed exponential distributionshave been used. The readers are referred to Chin (1977), Stern (1980), Richardson (1981),Stern and Coe (1984), Richardson and Wright (1984), Nicks and Gander (1994), Duan etal. (1998), Katz and Parlange (1998), Wilks (1999), Hayhoe (2000) and Wan et al. (2005)for some early discussion.However, a problem may arise under the traditional approach because the two stochasticmodels are assumed to be independent. Let us illustrate this point with an example usingthe traditional daily precipitation model for a xed period of mdays, where the number of

Associations between weather conditions and clinical symptoms in patients with hip osteoarthritis: A 2-year cohort study

The goal of this study was to assess whether there is an association between ambient weather conditions and patients’ clinical symptoms in patients with hip osteoarthritis (OA). The design was a cohort study with a 2-year follow-up and 3-monthly measurements and prospectively collected data on weather variables. The study population consisted of 222 primary care patients with hip OA. Weather variables included temperature, wind speed, total amount of sun hours, precipitation, barometric pressure, and relative humidity. The primary outcomes were severity of hip pain and hip disability as measured with the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) pain and function subscales. Associations between hip pain and hip disability and the weather variables were assessed using crude and multivariate adjusted linear mixed-model analysis for repeated measurements. On the day of questionnaire completion, mean relative humidity was associated with WOMAC pain (estimate 0.1; 95% confidence interval=0.0–0.2; P=.02). Relative humidity contributed ⩽1% to the explained within-patient variance and between-patient variance of the WOMAC pain score. Mean barometric pressure was associated with WOMAC function (estimate 0.1; 95% confidence interval=0.0–0.1; P=.02). Barometric pressure contributed ⩽1% to the explained within-patient variance and between-patient variance of the WOMAC function score. The other weather variables were not associated with the WOMAC pain or function score. Our results support the general opinion of OA patients that barometric pressure and relative humidity influence perceived OA symptoms. However, the contribution of these weather variables (⩽1%) to the severity of OA symptoms is not considered to be clinically relevant.

TR71 Bölgesi Yağlı Tohum Bitkileri Yetiştiriciliği ve İklim Değişikliğinin Etkileri

This study contains the yield evaluations on oilseed crops cultivation in TR71 region, which contains Niğde Kırşehir, Aksaray, Niğde and Nevşehir provinces and is also known as Ahiler Development Agency. Effects of climate change on oilseed crops based on climate projections of the next 30 years was have been analyzed. Changes in surface temperature values and precipitation amounts for the period of 2011-2041 have been evaluated seasonally and annually with the corresponding values of 1961-1990(RF). Based on the RegCM3-ECHAM5-A2 scenario, the average temperature is expected to increase 0.2-0.6 Co until 2041. The smallest temperature change is predicted to occur in spring season where the greatest temperature change (0,6-0,8C°) is expected to occur in summerand autumn season. The changes in total annual precipitation amounts had generally increase tendency (5-25%) over the region especially in winter season30% increase rate was expected over Kırşehir, Aksaray and South part of Kırıkkale province. The changes in total autumn season precipitation amount is predicted to increase (20%) over Niğde but decrease (5%) over the south part of Kırıkkale and southwest part of Kırşehir and Aksaray province in autumn season. Considering the effects of the climate change in the next 30 years, agricultural production in TR71 region is in quite a good place compared to other part of Turkey but this change will indeed affect the agricultural potential of the region substantially. Annual temperature elevation will aggravate the plant temperature stress where increased evaporation will negatively impact the yield, increasing the pressure on the limited irrigation potential. Especially elevated temperature will negatively impact disc development during the seed formation period resulting in yield loss because of the feeble seeds on the disc and the increased disease susceptibility resulting from the cavitation in the inner parts of the disc.

Impact of urbanization on low-temperature precipitation in Beijing during 1960–2008

Daily precipitation and temperature records at 13 stations for the period 1960–2008 were analyzed to identify climatic change and possible effects of urbanization on low-temperature precipitation [LTP, precipitation of ⩾ 0.1 mm d−1 occurring under a daily minimum temperature (Tmin) of ⩽ 0°C] in the greater Beijing region (BJR), where a rapid process of urbanization has taken place over the last few decades. The paper provides a climatological overview of LTP in BJR. LTP contributes 61.7% to the total amount of precipitation in BJR in the cold season (November–March). There is a slight increasing trend [1.22 mm (10 yr)−1] in the amount of total precipitation for the cold season during 1960-2008. In contrast, the amount of LTP decreases by 0.6 mm (10 yr)−1. The warming rate of Tmin in BJR is 0.66°C (10 yr)−1. Correspondingly, the frequency of LTP decreases with increasing Tmin by −0.67 times per °C. The seasonal frequency and amount of LTP in southeast BJR (mostly urban sites) are 17%–20% less than those in the northwestern (rural and montane sites). The intensity of LTP for the urban sites and northeastern BJR exhibited significant enhancing trends [0.18 and 0.15 mm d−1 (10 yr)−1, respectively]. The frequency of slight LTP (<0.2 mm d−1) significantly decreased throughout BJR [by about −15.74% (10 yr)−1 in the urban area and northeast BJR], while the contribution of the two heaviest LTP events to total LTP amount significantly increased by 3.2% (10 yr)−1.

Simulation of aerosol effects on orographic clouds and precipitation using WRF model with a detailed bin microphysics scheme

AbstractThe effects on orographic clouds and precipitation of aerosol loading have been investigated by simulating an idealized mixed‐phase orographic cloud using the Weather Research Forecast (WRF) mesoscale model coupled with a detailed bin microphysics scheme. The results show that the total precipitation amount is reduced by 23.4% with increasing aerosol loading on the orographic clouds. Moreover, increasing aerosol loading will increase the number concentration of cloud droplets in small size range (&lt;19.84 µm in diameter) and lead to a decrease in the peak diameter from 12.5 to 9.92 µm.

Parametrized diabatic processes in numerical simulations of an extratropical cyclone

The parametrization of diabatic processes in numerical models is critical for the accuracy of weather forecasts and for climate projections. A novel approach to the evaluation of these processes in models is introduced in this contribution. The approach combines a suite of on‐line tracer diagnostics with off‐line trajectory calculations. Each tracer tracks accumulative changes in potential temperature associated with a particular parametrized diabatic process in the model. A comparison of tracers therefore allows the identification of the most active diabatic processes and their downstream impacts. The tracers are combined with trajectories computed using model‐resolved winds, allowing the various diabatic contributions to be tracked back to their time and location of occurrence.We have used this approach to investigate diabatic processes within a simulated extratropical cyclone. We focus on the warm conveyor belt, in which the dominant diabatic contributions come from large‐scale latent heating and parametrized convection. By contrasting two simulations, one with standard convection parametrization settings and another with reduced parametrized convection, the effects of parametrized convection on the structure of the cyclone have been determined. Under reduced parametrized convection conditions, the large‐scale latent heating is forced to release convective instability which would otherwise have been released by the convection parametrization. Although the spatial distribution of precipitation depends on the details of the split between parametrized convection and large‐scale latent heating, the total precipitation amount associated with the cyclone remains largely unchanged. For reduced parametrized convection, a more rapid and stronger latent heating episode takes place as air ascends within the warm conveyor belt.

Controls on and impacts of the diurnal cycle of deep convective precipitation

Cumulus parameterizations have well‐known difficulties in capturing the diurnal cycle of tropical precipitation. This study explores the degree to which prescribed variations in cumulus mixing (entrainment/detrainment) can affect the precipitation diurnal cycle over a certain region and contribute to major climatic biases. This is achieved by artificially adjusting cumulus mixing rates as a function of time and location. It is found that variations in cumulus mixing can easily control the phase and amplitude of the oceanic precipitation diurnal cycle but not the total amount. The situation is different over land: the precipitation timing cannot be controlled by the mixing rates alone. Moreover, shifting the precipitation peak from noon to later times reduces the precipitation amplitude due to the strong diurnal cycle in convective triggering. This shift is accompanied by a reduction in net shortwave radiation and in latent heat flux (transpiration), which acts to reduce the total precipitation amount. The use of fixed SST and the absence of vegetation prevent a similar behavior over ocean. Climatic biases, as e.g., expressed by the location and structure of precipitation objects, seem not to be sensitive to the precipitation timing as long as the daily averaged precipitation remains similar. The differences are also smaller than differences induced by more structural changes performed to the convection scheme. Systematic but weak dependencies can mainly be isolated over the maritime continent, in the land‐to‐ocean precipitation ratio, in the location of the Atlantic ITCZ, in the surface fluxes over land, and in the net shortwave radiation.

Trends in precipitation extremes during the typhoon season in Taiwan over the last 60 years

The trends of four common climate change indices related to extreme precipitation events during the typhoon season (July–October) from 21 stations in Taiwan are investigated using a robust nonparametric method. Upward trends in precipitation intensity and 5‐day total precipitation amounts prevail from 1950 to 2010. Longer drought duration is also noted, in southern Taiwan in particular. Daily precipitation during the typhoon season is further partitioned into typhoon and monsoon rainfall. Precipitation intensity induced by typhoons and monsoon systems has both increased over the last 60 years; these two components collectively contribute to strong upward trend in precipitation intensity.

Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the Yellow River after 2000

The Hekou-Longmen reach, together with local floods, is the main source area for coarse sedimentations into the Yellow River. When total rainfall slightly increased in the area, discharge dramatically decreased by 40%–70% after the year of 2000, and attracting extensive attention in the context of global climate change. High temporal resolution precipitation (timescales between 1 and 4 h) data from the June to September period from 270 rain gauges over the past three decades was mined in order to help explain the phenomenon. Each rainfall event was classified as light/moderate rain, large rain, heavy rain or rainstorm by the event’s rainfall amount, and further classified as low intensity rain, medium intensity rain and high intensity rain by the event’s rainfall intensity. The Mann-Kendall trend test was applied to detect the presence and significance of monotonic trends, and to find the change points in the mean and variance of the precipitation characteristics series, including the amount, intensity, frequency and duration of each rainfall category. Results show that although the total amount of precipitation has slightly increased, the average rainfall intensity has significantly decreased. The larger change happened in light/moderate rain events and low/medium intensity rain events, and the intensity changes have a great extent occurred around the threshold of Non-Runoff Rainfall regime, which was proposed for the approximate calculation of initial losses. Changes in rainfall distribution between different classes of the Runoff Rainfall regime in the 2000s could lead to 0.9 mm less runoff depth (17.3% of the total reduction) than the 1980–1999 period. The study indicates that changes in hourly precipitation may be responsible for the sharp reduction of discharge.

Performance of herbaceous Evolvulus pilosus on urban green roof in relation to substrate and irrigation

Rooftop gardening (or green roof establishment) is an urban greening afforestation method that has many environmental, economic, and urban landscaping benefits. For rooftop vegetation, stressful environments that include heat, strong winds, sunshine, and drought prevent many plants from growing well, especially in shallow soil. To establish low cost urban rooftop gardens with a low weight substrate in the summer, we evaluated the green coverage and growth of a suitable groundcover ornamental plant, blue daze (Evolvulus pilosus). Blue daze was used as rooftop vegetation in a shallow substrate (10cm thick) on the flat rooftop of a four-story building in the middle of Kobe city, Japan, which has a temperate and humid climate. On average, the diurnal maximum temperatures and the total amounts of precipitation during each planting experiment between July and September were 30.8°C and 247mm in 2008 and 33.2°C and 458mm in 2009, respectively. Three different types of planting substrates (AS, amended soil, TM, turf mat as a dried-up blocks of sod, and FBA, furnace bottom ash) were tested to determine how they influenced plant cover, flowering, and growth. We evaluated the physical and chemical properties of the substrates that were used to establish the rooftop greeneries. In addition, the economy, ornamental and ecological values, reuse of material, and low rooftop weight burdens of the substrates were evaluated. The greatest blue daze ground cover occurred on the TM substrate (relative to the AS and FBA substrates) approximately three months after transplanting. The blue daze actively bloomed on all substrates throughout midsummer. However, alternate day irrigation largely reduced their shoot growth and flowering relative to daily irrigation. The AS and TM substrates had suitable physicochemical properties for use as planting substrates and had ideal solid, liquid, and vapor phase distributions and high water and nutrient holding capacities. FBA was a poor substrate with very low water and nutrient retention capacities, which resulted in depressed plant growth, especially under low watering conditions. To recycle FBA efficiently as a shallow low-cost planting substrate for rooftop gardening, the addition of coated fertilizers and organic matter to FBA should be considered to improve its water and nutrient holding capacities.

Assessing the robustness of projected precipitation changes over central Africa on the basis of a multitude of global and regional climate projections

It is well accepted within the scientific community that a large ensemble of different projections is required to achieve robust climate change information for a specific region. For this purpose we have compiled a state-of-the-art multi-model multi-scenario ensemble of global and regional precipitation projections. This ensemble combines several global projections from the CMIP3 and CMIP5 databases, along with some recently downscaled regional CORDEX-Africa projections. Altogether daily precipitation data from 77 different climate change projections is analysed; separated into 31 projections for a high and 46 for a low emission scenario. We find a robust indication that, independent of the underlying emission scenario, annual total precipitation amounts over the central African region are not likely to change severely in the future. However some robust changes in precipitation characteristics, like the intensification of heavy rainfall events as well as an increase in the number of dry spells during the rainy season are projected for the future. Further analysis shows that over some regions the results of the climate change assessment clearly depend on the size of the analyzed ensemble. This indicates the need of a “large-enough” ensemble of independent climate projections to allow for a reliable climate change assessment.

Aerosol effects on the cloud-field properties of tropical convective clouds

Abstract. Aerosol effects on condensed water and precipitation in a tropical cloud system driven by deep convective clouds are investigated for two-dimensional simulations of 2-day duration. Although an assumed 10-fold increase in aerosol concentration results in a similar temporal evolution of mean precipitation and a small (9%) difference in cumulative precipitation between the high- and low-aerosol cases, the characteristics of the convection are much more sensitive to aerosol. The convective mass flux, and temporal evolution and frequency distribution of the condensed water path WP (sum of liquid- and ice-water paths) differ significantly between unperturbed and aerosol-perturbed simulations. There are concomitant differences in the relative importance of individual microphysical processes and the frequency distribution of the precipitation rate (P). With increasing aerosol (i) the convective mass flux increases, leading to increases in condensation, cloud liquid, and accretion of cloud liquid by precipitation; (ii) autoconversion of cloud water to rain water decreases; (iii) the WP spatial distribution becomes more homogeneous; and (iv) there is an increase in the frequencies of high and low WP and P, and a decrease in these frequencies at the mid-range of WP and P. Thus, while aerosol perturbations have a small influence on total precipitation amount, for the case considered, they do have substantial influence on the spatiotemporal distribution of convection and precipitation.

The importance of precipitation timing for grassland productivity

Future climate change is likely to involve changes in the amount and intensity of precipitation, but also its timing during the year. To better understand how the timing of precipitation impacts plant productivity, a 27-year dataset on grass productivity for a mesic North American grassland was analyzed. Along with other climate parameters, the ability of the average date precipitation fell during different climate periods to explain grass productivity was tested. Across the 27 years, grass productivity was greater in years with more precipitation between April 15 and August 2. After accounting for differences in the total amount of precipitation during this time period, in years when precipitation between May 9 and August 27 fell later, measured grass productivity was less. Variation among years in precipitation timing was of similar importance as temperatures during critical climate periods and about 40 % of the importance of the total amount of precipitation. In all, although the mechanisms generating these responses are uncertain, precipitation timing within a growing season has substantial effects on productivity.

Corn Grain and Stover Yield Prediction at R1 Growth Stage

Estimating corn (Zea mays L.) grain and stover yield during the growing season is an appealing idea. An accurate yield estimation could benefit farmers, as well as corn‐related industries. The objective of this study was to develop regression equations to estimate corn grain and stover yield using easily accessible information (N fertilization rate and cumulative precipitation), and simple plant morphological measurements such as height, stem diameter at various heights, height of the first ear, and plants per hectare. Measurements made at silking (R1) were used since the maximum explainable variability would not exceed 58% at early stages of plant development (V2–V10; between 2‐leaf and 10‐leaf stages). The experiment was conducted from 2009 until 2011 in two locations, in north and central Alabama, under no‐tillage and non‐irrigated conditions. Treatments were assigned to a 3 × 4 × 2 complete factorial design arranged in a split‐split‐plot with three replications. Factors were; winter rye (Secale cereale L.) cover crop (main plot), N fertilization rates (subplot), and stover residue harvest (sub‐subplot). All measurements from this study, across years and locations, were used in the final regression equations to create robust prediction models. Equations, with and without intercept, were developed and compared according to several statistical criteria. The final grain yield equation at R1 growth stage included an intercept with a R2 of 0.7705. The final stover equation also included an intercept (R2 = 0.8473). This study suggests that N rate, total precipitation amount from planting until silking, and simple plant morphological measurements can be used to predict corn yield.

Spring and summer patterns in flowering onset, duration, and constancy across a water‐limited gradient

Community-level flowering patterns can be characterized by onset, duration, and end as well as constancy, the degree to which species commence, cease, and reinitiate flowering within a season. In the mountainous Sky Islands region of the southwestern United States, flowering onset is clearly influenced by elevation in the spring, but much less so in the summer season. We evaluated whether these flowering metrics reflect these dissimilar patterns between distinct spring and summer seasons regarding the influence of the elevation and moisture gradient. • We characterized flowering onset, end, duration, and constancy by plant functional type and their relationships to climate variables in spring and summer. We also evaluated the influence of climate on seasonal flowering patterns. • Gaps in seasonal flowering occur frequently in this system in both seasons and among all plant functional types. In both seasons, annual plants exhibit the shortest flowering durations and highest constancies, and plants at low elevations, inhabiting environments with variable moisture conditions, show a greater tendency for longer flowering durations and lower constancy than high-elevation plants. Spring flowering characteristics are most influenced by the total amount of October-March precipitation as well as temperatures in these months, whereas summer flowering characteristics are influenced by the timing of summer-season precipitation, and next by the total amount of summer precipitation. • Flowering metrics, especially constancy and duration, show similar patterns in spring and summer and vary across elevation and moisture gradients. These patterns have substantial implications for plant and animal communities.

Spatiotemporal variations of precipitation regimes across Yangtze River Basin, China

Daily precipitation data during the period of 1960 to 2005 from 147 rain gauging stations over the Yangtze River Basin are analyzed to investigate precipitation variations based on precipitation indices and also consecutive rainfall regimes in both space and time. Results indicate decreasing annual/monthly mean precipitation. Distinct decreases in rainfall days are observed over most parts of the Yangtze River Basin, but precipitation intensity is increasing over most parts of the Yangtze River Basin, particularly the lower Yangtze River Basin. Besides, durations of precipitation regimes are shortening; however, the fractional contribution of short-lasting precipitation regimes to the total precipitation amount is increasing. In this sense, the precipitation processes in the Yangtze River Basin are dominated by precipitation regimes of shorter durations. These results indicate intensified hydrological cycle reflected by shortening precipitation regimes. This finding is different from that in Europe where the intensifying precipitation changes are reflected mainly by lengthening precipitation regimes, implying different regional responses of hydrological cycle to climate changes. The results of this study will be of considerable relevance in basin-scale water resources management, human mitigation of natural hazards, and in understanding regional hydrological responses to changing climate at regional scales.