Comparison of Active COVID-19 Cases per Population Using Time-Series Models

This research explored the precision of diverse time-series models for COVID-19 epidemic detection in all the thirty-six different states and the Federal Capital Territory (FCT) in Nigeria with the maximum count of daily cumulative of confirmed, recovered and death cases as of 4 November 2020 of COVID-19 and populace of each state. A 14-multi step ahead forecast system for active coronavirus cases was built, analyzed and compared for six (6) different deep learning-stimulated and statistical time-series models using two openly accessible datasets. The results obtained showed that based on RMSE metric, ARIMA model obtained the best values for four of the states (0.002537, 0.001969.12E-058, 5.36E-05 values for Lagos, FCT, Edo and Delta states respectively). While no method is all-encompassing for predicting daily active coronavirus cases for different states in Nigeria, ARIMA model obtains the highest-ranking prediction performance and attained a good position results in other states.

Comparison of Active COVID-19 Cases Per Population Using Time-Series Models

This research explored the precision of diverse time-series models for COVID-19 epidemic detection in all the thirty-six different states and the Federal Capital Territory (FCT) in Nigeria with the maximum count of daily cumulative of confirmed, recovered and death cases as of 4 November 2020 of COVID-19 and populace of each state. A 14-multi step ahead forecast system for active coronavirus cases was built, analyzed and compared for six (6) different deep learning-stimulated and statistical time-series models using two openly accessible datasets. The results obtained showed that based on RMSE metric, ARIMA model obtained the best values for four of the states (0.002537, 0.001969.12E-058, 5.36E-05 values for Lagos, FCT, Edo and Delta states respectively). While no method is all-encompassing for predicting daily active coronavirus cases for different states in Nigeria, ARIMA model obtains the highest-ranking prediction performance and attained a good position results in other states.

Impact of ERS-2 Scatterometer wind data on Global Analysis-Forecast system

The near surface scatterometer wind data from the European remote sensing satellite ERS-2 of European space agency(ESA) became available at NCMRWF on real time basis since February 1997. An attempt has been made to assimilate this data in the global data assimilation system(GDAS) operational at NCMRWF after proper quality control to study its impact on the analysis as well as on medium range weather forecast over the tropics. For this purpose the GDAS was run for 15 days (27 May to 10 June 1998). The impact has been examined through circulation characteristics and various objective scores. The study revealed that with proper quality control the scatterometer wind data can be assimilated in real time basis, resulting in an overall improvement in performance of the analysis-forecast system.

On the quality of RS41 radiosonde descent data

Radiosonde descent profiles have been available from tens of stations for several years now – mainly from Vaisala RS41 radiosondes. They have been compared with the ascent profiles, with ECMWF short-range forecasts and with co-located radio occultation retrievals. Over this time, our understanding of the data has grown, and the comparison has also shed some light on radiosonde ascent data. The fall rate is very variable and is an important factor, with high fall rates being associated with temperature biases, especially at higher altitudes. Ascent winds are affected by pendulum motion; on average, descent winds are less affected by pendulum motion and are smoother. It is plausible that the true wind variability in the vertical lies between that shown by ascent and descent profiles. This discrepancy indicates the need for reference wind measurements. With current processing, the best results are for radiosondes with parachutes and pressure sensors. Some of the wind, temperature and humidity data are now assimilated in the ECMWF forecast system.

A case study of the impact of INSAT derived humidity profiles on precipitation forecast by limited area model

The impact of humidity profiles estimated from INSAT digital IR cloud imagery data on initial moisture analysis in the IMD's operational limited area forecast system has been investigated. Method for assimilation of humidity profiles data as pseudo observations in the analysis scheme has been developed and implemented in the regional analysis scheme. Verification of humidity analysis with this data has shown substantial improvements in the moisture analysis over the data sparse region of tropics. Impact of the improved humidity analysis on model predicted rainfall is examined. The experiments show improved rainfall prediction.

GEFSv12 reforecast dataset for supporting subseasonal and hydrometeorological applications

For the newly implemented Global Ensemble Forecast System version 12 (GEFSv12), a 31-year (1989-2019) ensemble reforecast dataset has been generated at the National Centers for Environmental Prediction (NCEP). The reforecast system is based on NCEP’s Global Forecast System version 15.1 and GEFSv12, which uses the Finite Volume 3 dynamical core. The resolution of the forecast system is ∼25 km with 64 vertical hybrid levels. The Climate Forecast System (CFS) reanalysis and GEFSv12 reanalysis serve as initial conditions for the Phase 1 (1989–1999) and Phase 2 (2000–2019) reforecasts, respectively. The perturbations were produced using breeding vectors and ensemble transforms with a rescaling technique for Phase 1 and ensemble Kalman filter 6-h forecasts for Phase 2. The reforecasts were initialized at 0000 (0300) UTC once per day out to 16 days with 5 ensemble members for Phase 1 (Phase 2), except on Wednesdays when the integrations were extended to 35 days with 11 members. The reforecast data set was produced on NOAA’s Weather and Climate Operational Supercomputing System at NCEP. This study summarizes the configuration and dataset of the GEFSv12 reforecast and presents some preliminary evaluations of 500hPa geopotential height, tropical storm track, precipitation, 2-meter temperature, and MJO forecasts. The results were also compared with GEFSv10 or GEFS Subseasonal Experiment reforecasts. In addition to supporting calibration and validation for the National Water Center, NCEP Climate Prediction Center, and other National Weather Service stakeholders, this high-resolution subseasonal dataset also serves as a useful tool for the broader research community in different applications.

Exploring the Usefulness of Downscaling Free Forecasts from the Warn-on-Forecast System

The National Severe Storms Lab (NSSL) Warn-on-Forecast System (WoFS) is an experimental real-time rapidly-updating convection-allowing ensemble that provides probabilistic short-term thunderstorm forecasts. This study evaluates the impacts of reducing the forecast model horizontal grid spacing Δx from 3 km to 1.5 km on the WoFS deterministic and probabilistic forecast skill, using eleven case days selected from the 2020 NOAA Hazardous Weather Testbed (HWT) Spring Forecasting Experiment (SFE). Verification methods include (i) subjective forecaster impressions; (ii) a deterministic object-based technique that identifies forecast reflectivity and rotation track storm objects as contiguous local maxima in the composite reflectivity and updraft helicity fields, respectively, and matches them to observed storm objects; and (iii) a recently developed algorithm that matches observed mesocyclones to mesocyclone probability swath objects constructed from the full ensemble of rotation track objects. Reducing Δx fails to systematically improve deterministic skill in forecasting reflectivity object occurrence, as measured by critical success index (CSIDET), a metric that incorporates both probability of detection (PODDET) and false alarm ratio (FARDET). However, compared to the Δx = 3 km configuration, the Δx = 1.5 km WoFS shows improved mid-level mesocyclone detection, as evidenced by its statistically significant (i) higher CSIDET for deterministic mid-level rotation track objects and (ii) higher normalized area under the performance diagram curve (NAUPDC) score for probability swath objects. Comparison between Δx = 3 km and Δx = 1.5 km reflectivity object properties reveals that the latter have 30% stronger mean updraft speeds, 17% stronger median 80-m winds, 67% larger median hail diameter, and 28% higher median near-storm-maximum 0-3 km storm-relative helicity.

EFECTO DE LA CORRIENTE EN CHORRO DE BAJOS NIVELES EN LA OCURRENCIA DE PRECIPITACIÓN EN LA SELVA DEL PERÚ

Se analizó la corriente en chorro de América del Sur (SALLJ, siglas en inglés) y la ocurrencia de precipitación sobre la selva del Perú, tomando en cuenta los datos del modelo atmosférico Global Forecast System (GFS) y datos de precipitación acumulada estimado por el satélite Tropical Rainfall Measuring Mission (TRMM) en los veranos australes comprendidos entre los años 2005 y 2014. Se utilizó la distribución de Weibull para el análisis estadístico del viento meridional del norte y el test estadístico no paramétrico de correlación de Kendall para asociar los eventos SALLJ definidos por los criterios de Whiteman et al. (1997) y Bonner (1968). Los resultados revelan que el comportamiento promedio de la componente meridional del viento fluctúa entre 1.2 y 11.7 m/s con variaciones de +/- 3.2 m/s, registrando un viento máximo de 21.4 m/s. De un total de 39 casos, el 53.8% se identificó con las condiciones propuestas por Whiteman y un 46.2% con las condiciones de Bonner. Se registró una precipitación máxima de 64.00 mm/día y mayor número de días con precipitaciones asociadas a eventos SALLJ para las 00 UTC.

About the possibility of using the output data of the global atmosphere model GFS NCEP in ecological research

Проведена оценка степени совпадения прогностических значений стратификации атмосферы с нарастающей заблаговременностью 24 часа, полученных из глобальной модели атмосферы GFS NCEP (Global Forecast System National Centers for Environmental Prediction) с фактическими данными аэрологического зондирования на основе корреляционного анализа. Актуальность работы заключается в том, что в настоящее время количество опасных природных явлений продолжает увеличиваться, в том числе и загрязнение атмосферы примесями, приводящими к глобальному потеплению. При прогнозировании опасных явлений для экологии входными данными являются значения полей метеопараметров по фактическим данным аэрологического зондирования атмосферы. Такие данные доступны только на отдельных метеостанциях, расположенных достаточно далеко друг от друга, что усложняет проведение исследований. Между тем инструменты для анализа и оценки распространения и рассеивания загрязняющих веществ в атмосфере в настоящее время получили значительное развитие. Сдерживающим фактором их более широкого применения заинтересованными структурами по прогнозированию качества воздуха, аварийно-спасательными службами, представителями авиации, государственными учреждениями и сообществом исследователей атмосферы является недостаток информации о текущем состоянии атмосферы, а также получение прогностических метеопараметров. Для решения этой проблемы предлагаются использовать данные глобальной модели атмосферы GFS NCEP. Целью исследования является определить правомерность замены фактических данных аэрологического зондирования атмосферы на прогностические поля стратифицированных метеопараметров из глобальной модели атмосферы. Методом исследования является один из методов статистического анализа данных - корреляционный анализ. В результате исследований получено, что коэффициенты корреляции между прогностическими и фактическими значениями температуры воздуха, температуры точки росы, скорости и направления ветра имеют высокие значения. Это делает возможными использование данных глобальной модели при математическом моделировании распространения загрязнения в атмосфере, а также прогнозе опасных стихийных явлений, таких как паводок, сильный ливень, град, сель, приводящих к нарушению природных экологических систем. The degree of matching of the predictive values of atmosphere stratification with an increasing lead time of 24 hours obtained from the global atmosphere model GFS NCEP (Global Forecast System National Centers for Environmental Prediction) and the actual data of aerological sounding based on correlation analysis was assessed. The relevance of the work lies in the fact that at present the number of natural hazards continues to increase, including atmospheric pollution with impurities leading to global warming. When predicting dangerous phenomena for the environment, the input data are the values of the fields of meteorological parameters based on the actual data of the aerological sounding of the atmosphere. Such data is available only at individual weather stations located far enough apart from each other, which complicates the research. Meanwhile, tools for analyzing and assessing the spread and dispersion of pollutants in the atmosphere have now received significant development. A limiting factor in their wider use by interested structures for predicting air quality, emergency services, aviation representatives, government agencies and the community of atmosphere researchers is the lack of information about the current state of the atmosphere, as well as obtaining predictive meteorological parameters. To solve this problem, data from the global atmosphere model GFS NCEP are proposed. The aim of the study is to determine the validity of replacing the actual data of the aerological sounding of the atmosphere with the predictive fields of stratified meteorological parameters from the global atmosphere model. The research method is correlation analysis, one of the methods of statistical data analysis. As a result of the research, it was found that the correlation coefficients between the predictive and actual values of air temperature, dew point temperature, wind speed and direction have high values. This makes it possible to use the data of the global model in mathematical modeling of atmospheric pollution, as well as the forecast of dangerous natural phenomena, such as floods, heavy rain, hail, mudslides, leading to disruption of natural ecological systems.