scholarly journals Multi-RCM ensemble downscaling of NCEP CFS winter season forecasts: Implications for seasonal hydrologic forecast skill

2013 ◽  
Vol 118 (19) ◽  
pp. 10,770-10,790 ◽  
Author(s):  
Shraddhanand Shukla ◽  
Dennis P. Lettenmaier
Keyword(s):  
Winter Season ◽  
Forecast Skill ◽  
Hydrologic Forecast ◽  
Ncep Cfs

scholarly journals Yearly evolution of Euro-Atlantic weather regimes and of their sub-seasonal predictability

2021 ◽  
Author(s):  
Nicola Cortesi ◽  
Verónica Torralba ◽  
Llorenó Lledó ◽  
Andrea Manrique-Suñén ◽  
Nube Gonzalez-Reviriego ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Winter Season ◽  
Skill Score ◽  
Seasonal Forecast ◽  
Forecast Skill ◽  
Seasonal Forecasts ◽  
Sea Level Pressure ◽  
Weather Regimes ◽  
Start Dates ◽  
Weekly Frequency

AbstractIt is often assumed that weather regimes adequately characterize atmospheric circulation variability. However, regime classifications spanning many months and with a low number of regimes may not satisfy this assumption. The first aim of this study is to test such hypothesis for the Euro-Atlantic region. The second one is to extend the assessment of sub-seasonal forecast skill in predicting the frequencies of occurrence of the regimes beyond the winter season. Two regime classifications of four regimes each were obtained from sea level pressure anomalies clustered from October to March and from April to September respectively. Their spatial patterns were compared with those representing the annual cycle. Results highlight that the two regime classifications are able to reproduce most part of the patterns of the annual cycle, except during the transition weeks between the two periods, when patterns of the annual cycle resembling Atlantic Low regime are not also observed in any of the two classifications. Forecast skill of Atlantic Low was found to be similar to that of NAO+, the regime replacing Atlantic Low in the two classifications. Thus, although clustering yearly circulation data in two periods of 6 months each introduces a few deviations from the annual cycle of the regime patterns, it does not negatively affect sub-seasonal forecast skill. Beyond the winter season and the first ten forecast days, sub-seasonal forecasts of ECMWF are still able to achieve weekly frequency correlations of r = 0.5 for some regimes and start dates, including summer ones. ECMWF forecasts beat climatological forecasts in case of long-lasting regime events, and when measured by the fair continuous ranked probability skill score, but not when measured by the Brier skill score. Thus, more efforts have to be done yet in order to achieve minimum skill necessary to develop forecast products based on weather regimes outside winter season.

scholarly journals Stratospheric Nudging And Predictable Surface Impacts (SNAPSI): A Protocol for Investigating the Role of the Stratospheric Polar Vortex in Subseasonal to Seasonal Forecasts

2022 ◽  
Author(s):  
Peter Hitchcock ◽  
Amy Butler ◽  
Andrew Charlton-Perez ◽  
Chaim Garfinkel ◽  
Tim Stockdale ◽  
...  
Keyword(s):  
Winter Season ◽  
Polar Vortex ◽  
Forecast Skill ◽  
The Arctic ◽  
Seasonal Forecasts ◽  
Stratospheric Polar Vortex ◽  
Near Surface ◽  
Forecast Models ◽  
The Impact

Abstract. Major disruptions of the winter season, high-latitude, stratospheric polar vortices can result in stratospheric anomalies that persist for months. These sudden stratospheric warming events are recognized as an important potential source of forecast skill for surface climate on subseasonal to seasonal timescales. Realizing this skill in operational subseasonal forecast models remains a challenge, as models must capture both the evolution of the stratospheric polar vortices in addition to their coupling to the troposphere. The processes involved in this coupling remain a topic of open research. We present here the Stratospheric Nudging And Predictable Surface Impacts (SNAPSI) project. SNAPSI is a new model intercomparison protocol designed to study the role of the Arctic and Antarctic stratospheric polar vortices in sub-seasonal to seasonal forecast models. Based on a set of controlled, subseasonal, ensemble forecasts of three recent events, the protocol aims to address four main scientific goals. First, to quantify the impact of improved stratospheric forecasts on near-surface forecast skill. Second, to attribute specific extreme events to stratospheric variability. Third, to assess the mechanisms by which the stratosphere influences the troposphere in the forecast models, and fourth, to investigate the wave processes that lead to the stratospheric anomalies themselves. Although not a primary focus, the experiments are furthermore expected to shed light on coupling between the tropical stratosphere and troposphere. The output requested will allow for a more detailed, process-based community analysis than has been possible with existing databases of subseasonal forecasts.

scholarly journals Forecast Skill for California Heavy Precipitation Periods from the High-Resolution Rapid Refresh Model and the Coupled Ocean-Atmospheric Mesoscale Prediction System

2021 ◽  
Author(s):  
Kevin J. Dougherty ◽  
John D. Horel ◽  
Jason E. Nachamkin
Keyword(s):  
High Resolution ◽  
Spatial Scales ◽  
Winter Season ◽  
Coastal Region ◽  
Heavy Precipitation ◽  
Skill Score ◽  
Winter Precipitation ◽  
Forecast Skill ◽  
Precipitation Forecast ◽  
Prediction System

AbstractPrecipitation forecasts from the High-Resolution Rapid Refresh model (HRRR) of the National Centers for Environmental Prediction (NCEP) and the Navy’s Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS) are examined during heavy precipitation periods in California. Precipitation forecast discrepancies between the two models are examined during a recent heavy winter precipitation episode in California from 6-8 December 2019. The skill of initial 12-h precipitation forecasts is examined objectively from 1 December 2018 – 28 February 2019 from the HRRR, COAMPS, and NCEP’s North American Mesoscale Forecast System (NAM-3km). The HRRR exhibited lower seasonal biases and higher skill based on several metrics applied to a sample of 48 12-h periods during California’s second wettest winter season during the past 20 years. Overall, the NAM-3km and COAMPS exhibited a large wet bias over the interior mountain regions while the HRRR model indicated a dry bias along the northern coastal region. All models tended to underestimate precipitation along the coastal mountains of northern California. To highlight the regional and localized nature of forecast skill, the Fraction Skill Score (FSS) metric is applied across ranges of spatial scales and precipitation values. For the domain as a whole, the HRRR had higher precipitation forecast skill compared to the other two models, particularly within radial distances of 20-30 km and moderate (10-50 mm) precipitation totals. FSS computed locally highlights the HRRR’s overall higher skill as well as enhanced skill in the southern half of the state.

scholarly journals Seasonal hydrologic prediction in the United States: understanding the role of initial hydrologic conditions and seasonal climate forecast skill

2011 ◽  
Vol 15 (11) ◽  
pp. 3529-3538 ◽  
Author(s):  
S. Shukla ◽  
D. P. Lettenmaier
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Forecast Skill ◽  
Climate Forecast ◽  
Streamflow Prediction ◽  
Seasonal Climate ◽  
Western Us ◽  
Ensemble Streamflow Prediction ◽  
Hydrologic Forecast ◽  
Hydrologic Conditions

Abstract. Seasonal hydrologic forecasts derive their skill from knowledge of initial hydrologic conditions and climate forecast skill associated with seasonal climate outlooks. Depending on the type of hydrological regime and the season, the relative contributions of initial hydrologic conditions and climate forecast skill to seasonal hydrologic forecast skill vary. We seek to quantify these contributions on a relative basis across the Conterminous United States. We constructed two experiments – Ensemble Streamflow Prediction and reverse-Ensemble Streamflow Prediction – to partition the contributions of the initial hydrologic conditions and climate forecast skill to overall forecast skill. In ensemble streamflow prediction (first experiment) hydrologic forecast skill is derived solely from knowledge of initial hydrologic conditions, whereas in reverse-ensemble streamflow prediction (second experiment), it is derived solely from atmospheric forcings (i.e. perfect climate forecast skill). Using the ratios of root mean square error in predicting cumulative runoff and mean monthly soil moisture of each experiment, we identify the variability of the relative contributions of the initial hydrologic conditions and climate forecast skill spatially throughout the year. We conclude that the initial hydrologic conditions generally have the strongest influence on the prediction of cumulative runoff and soil moisture at lead-1 (first month of the forecast period), beyond which climate forecast skill starts to have greater influence. Improvement in climate forecast skill alone will lead to better seasonal hydrologic forecast skill in most parts of the Northeastern and Southeastern US throughout the year and in the Western US mainly during fall and winter months; whereas improvement in knowledge of the initial hydrologic conditions can potentially improve skill most in the Western US during spring and summer months. We also observed that at a short lead time (i.e. lead-1) contribution of the initial hydrologic conditions in soil moisture forecasts is more extensive than in cumulative runoff forecasts across the Conterminous US.

scholarly journals Seasonal hydrologic prediction in the United States: understanding the role of initial hydrologic conditions and seasonal climate forecast skill

2011 ◽  
Vol 8 (4) ◽  
pp. 6565-6592 ◽  
Author(s):  
S. Shukla ◽  
D. P. Lettenmaier
Keyword(s):  
United States ◽  
The United States ◽  
Forecast Skill ◽  
Climate Forecast ◽  
Streamflow Prediction ◽  
Seasonal Climate ◽  
Southeastern Us ◽  
Western Us ◽  
Hydrologic Forecast ◽  
Hydrologic Conditions

Abstract. Seasonal hydrologic forecasts derive their skill from knowledge of initial hydrologic conditions (IHCs) and climate forecast skill (CFS) associated with seasonal climate outlooks. Depending on the type of hydrological regime and the season, the relative contributions of IHCs and CFS to seasonal hydrologic forecast skill vary. We seek to quantify these contributions on a relative basis across the Conterminous United States (CONUS). We constructed two experiments – Ensemble Streamflow Prediction (ESP) and reverse-ESP – to partition the contributions of the IHCs and CFS to overall forecast skill. In ESP hydrologic forecast skill is derived solely from knowledge of IHCs, whereas in reverse-ESP (second experiment), it is derived solely from atmospheric forcings (i.e. perfect CFS). Using the ratios of root mean square error (RMSE) in predicting cumulative runoff (CR) and mean monthly soil moisture (SM) of each experiment, we identify the variability of the relative contributions of the IHCs and CFS spatially throughout the year. We conclude that the IHCs generally have the strongest influence on the prediction of CR and SM at lead-1 (first month of the forecast period), beyond which CFS starts to have greater influence. Improvement in CFS alone will lead to better seasonal hydrologic forecast skill in most parts of the northeastern and southeastern US throughout the year and in the western US mainly during fall and winter months; whereas improvement in knowledge of the IHCs can potentially improve skill most in the western US during spring and summer months. We also observed that at short lead time (i.e. lead-1) contribution of the IHCs in SM forecasts is more extensive than in CR forecasts across the CONUS.

PREVALENCE OF PSEUDOINVERTA ORAIENSIS IN FRESH WATER FISH, CLARIAS BATRACHUS

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
ADITYA NARAYAN
Keyword(s):  
Fresh Water ◽  
Monsoon Season ◽  
Winter Season ◽  
Uttar Pradesh ◽  
Summer Season ◽  
Clarias Batrachus ◽  
Fresh Water Fish ◽  
Water Fish

The present investigation deals with the prevalence of infection of cestode, Pseudoinverta oraiensis19 parasitizing Clarias batrachus from Bundelkhand Region (U.P.) India. The studies were recorded from different sampling stations of Bundelkhand region of Uttar Pradesh. For this study 360 fresh water fish, Clarias batrachus were examined. The incidence of infection, monsoon season (17.50%) followed by winter season (20.00%) whereas high in summer season (30.00%).

STUDY ON DIVERSITY AND DISTRIBUTION OF ANTS (HYMENOPTERA: FORMICIDAE) IN URBAN AND PERIURBAN AREAS OF AURANGABAD CITY, MAHARASHTRA, INDIA

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
S. D. CHATE ◽  
R. J. CHAVAN
Keyword(s):  
Rainy Season ◽  
Winter Season ◽  
Seasonal Abundance ◽  
Urban Region ◽  
Ant Community ◽  
Community Variation

The present study deals with the ant community variation in and around Aurangabad city. During the study total 16 species of ants belonging to twelve genera and four subfamilies were reported in eight habitat from urban and periurban regions. Abundance of ants was more in peri-urban region as compared to urban region. Subfamily myrmicinae was more dominant as compared to other subfamilies. Seasonal abundance of ants was seen to be more in winter season and less in rainy season.

A Cross Sectional Survey of Chicken Astroviruses Antibody in Broiler and Sonali (Cross-Bred) Chickens in Selected Areas in Bangladesh

2020 ◽  
Vol 43 (1) ◽  
pp. 75-80
Author(s):  
Md Zulfekar Ali ◽  
Mohammad Moktader Moula ◽  
Zafar Ahmed Bhuiyan ◽  
Muhammad Tariq Javed
Keyword(s):  
Age Groups ◽  
Winter Season ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Blood Samples ◽  
Elisa Kit ◽  
Published Report ◽  
Poultry Birds ◽  
Wide Range ◽  
Group B

AbstractChicken astroviruses (CAstV) are enteric viruses of poultry causing gastroenteritis, malabsorption, gout and white chick disease commonly known as runting-stunting syndrome (RSS). It can affect the wide range of poultry birds, especially chicken, turkey and duck worldwide. To our best knowledge there is no published report on presence of antibodies against CAstV in Bangladesh. Therefore, the study aimed to detect the presence of CAstV antibodies in broilers and sonali chickens (a cross-bread) in Bangladesh through a cross-sectional survey. A total of 454 blood samples from 66 flocks of broiler (n=343) and sonali chickens (n=111) of different ages were obtained during 2017 from four districts. The birds were healthy but were not vaccinated against CAstV. The samples were tested for specific antibodies against CAstV Group B by using commercially available ELISA kit. Overall, 16.74% (76/454) samples and 34.84% (23/66) flocks were positive for CAstV antibodies. The seroprevalence of CAstV was significantly (p=0.001) higher in sonali chickens (36.96%) than broiler (10.20%), while it was significantly higher (p=0.001) in birds of Bogura district (36.94%) than the other three districts. Regarding the age groups, seroprevalence was insignificantly (p=0.192) higher in sonali chicken before laying age (45%) than during laying age (27.45%). Regarding the seasons, CAstV infection was prevalent significantly (p=0.001) higher in winter season. Thus, the present study indicated the presence of CAstV in poultry in Bangladesh, so further studies are required to find out the magnitude of the problem in the country.

APPLICATION OF SHIFTING ASSAY OF STANDARDIZED INDIRECT AGGLUTINATION (SSIA) FOR DETECTION OF ANTIGENS OF NEWCASTLE DISEASE AND INFECTIOUS BURSAL DISEASE VIRUSES IN CHICKEN FAECES

2013 ◽  
Vol 83 (5) ◽  
Author(s):  
Phạm Hồng Sơn ◽  
Phạm Hồng Kỳ ◽  
Nguyễn Thị Lan Hương ◽  
Phạm Thị Hồng Hà
Keyword(s):  
Newcastle Disease ◽  
Winter Season ◽  
Summer Season ◽  
Infectious Bursal Disease ◽  
Infection Rates ◽  
Faecal Samples ◽  
Infectious Bursal Disease Viruses ◽  
Bursal Disease ◽  
Long Time ◽  
Higher Sensitivity

. Using the method of shifting assay of standardized indirect agglutination (SSIA), the prevalence of Newcastle disease viruses (NDV) and infectious bursal disease viruses (IBDV) in chickens reared in several districts of Thua Thien Hue province in the Spring-Summer and Fall-Winter seasons was determined. In the Spring-Summer season of 2011, about 22.3% of the chickens were infected with NDV, in which A Luoi  accounted for the highest percentage of 25% of the infected chickens and Huong Thuy  the lowest  of 18.2%. Meanwhile, 36% of the same chickens were infected with IBDV, with the highest percentage (46.66%) also in A Luoi and the lowest (30.3%) also in Huong Thuy. The intensity of NDV infection in the Spring-Summer season in A Luoi and Phu Vang was highest (GMT = 1.45), and in Huong Thuy lowest (GMT = 1.31). In addition, in the Fall-Winter season, about 46% of the chickens were infected with NDV and 46.3% with IBDV in Huong Thuy and Phu Vang – two neighbouring districts of Hue City, in which NDV was detected in 54.4% of the chickens in Huong Thuy and 33.9% in Phu Vang. In contrast, IBDV was detected in 41.9% and 52.7% of the chickens respectively in the two districts. The infection was not inter-dependent. Methodically, although the differences in the infection rates were insignificant with the accuracy of 95%, faecal samples showed higher sensitivity in SSIA analyses for both cases of NDV and IBDV infection in comparision with mouth exudates. By SSIA method, results could be read clearly with unaided eyes for a long time after the performance, and it was also proven applicable for cases of haemagglutinating viruses if proper treatments for depletion of animal RBCs’ surface agglutinins could be applied.

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