Long-range prediction of monsoon onset over Kerala

ABSTRACT. Using the data of 33 years ( 1961-1993) the effect of the intensity of heat low over central India during the Month of April and Winter (December to February) Eurasian snow cover on interannual variation of monsoon date over Kerala were examined. Composite mean surface temperature over central India during the month of April was higher during early onset years by 3.5° C. April mean surface temperature index (MST) and Winter (December to February) Eurasian snow cover (WSC) are significantly correlated with Monsoon onset dates al 1% and 5% significant levels respectively. Lower surface temperature and excessive snow cover indicate a late onset. A regression equation was developed for long range prediction of onset date over Kerala using MST and WSC as independent variables. The root mean square error (RMSE) of the relationship was found to be 4.6 days. The model was tested using independent data of five years and was found performing well. Contingency tables were developed between the pairs MOD and WSC and MOD and MST. The tables can be used for probability forecasts of early and late onset years.

EMPIRICAL ORTHOGONAL FUNCTIONS ASSOCIATED WITH PARAMETERS USED IN LONG RANGE FORECASTING OF INDIAN SUMMER MONSOON

EEmpirical Orthogonal Functions (EOF),. associated with the; parameters for long range forecasting of Indian summer monsoon onset and seasonal. rainfall have been discussed. It was found that the percentage of variance explained was 77 and 67 respectively through the first four EOF. The highest correlation coefficient with the onset date was found for the first function which showed the maximum influence of Cobar (Australia) and Darwin (Australia) zonal winds on the onset date. It was interesting to note that for rainfall prediction predominant effect on the first EOF was noticed of 50 hPa ridge over northern hemisphere, Eurasian snow cover, Argentina pressure (negatively correlated) and 500 hpa ridge, 10 hPa Balboa wind, north, central India and east coast minimum temperatures, and northern hemisphere temperature. However, the Influence of EI-Nino, equatorial pressure and Darwin pressure (Including Tahiti minus Darwin) and Himalayan snow cover was almost negligible. The eigen index for the onset date suggests a complementary method for its application In long range prediction of summer monsoon onset date.

Objective determination of northeast monsoon onset dates over coastal Tamil Nadu for the period 1901-90

The onset dates of northeast monsoon over coastal Tamil Nadu have been determined by adopting an objective method for the years 1901-90. The various statistical parameters associated with onset dates have been computed and interpreted. Relation between onset dates of easterlies and northeast monsoon over Tamil Nadu has been examined. The normal date obtained has been shown to be by and large consistent with the characteristics of normal daily rainfall of coastal Tamil Nadu. The superposed epoch method has been, used to compute the mean rainfall with reference to onset date and the abrupt increase in rainfall at onset has been clearly brought out The spatial distribution and intensity of rainfall at the time of onset have also been discussed. Daily rainfall has been graphically presented for some years with spectacular onset as well as for some years with subdued onset.

Early estimates of SARS-CoV-2 Omicron variant severity based on a matched cohort study, Ontario, Canada

While it is now evident that Omicron is rapidly replacing Delta, due to a combination of increased transmissibility and immune escape, it is less clear how the severity of Omicron compares to Delta. In Ontario, we sought to examine hospitalization and death associated with Omicron, as compared to matched cases infected with Delta. We conducted a matched cohort study, considering time to hospitalization or death as the outcome, and analyzed with a Cox proportional hazards model. Cases were matched on age, gender, and onset date, while vaccine doses received and time since vaccination were included as adjustment variables. We identified 6,314 Omicron cases that met eligibility criteria, of which 6,312 could be matched with at least one Delta case (N=8,875) based on age, gender, and onset date. There were 21 (0.3%) hospitalizations and 0 (0%) deaths among matched Omicron cases, compared to 116 (2.2%) hospitalizations and 7 (0.3%) deaths among matched Delta cases. The adjusted risk of hospitalization or death was 54% lower (HR=0.46, 95%CI: 0.27, 0.77) among Omicron cases compared to Delta cases. While severity may be reduced, the absolute number of hospitalizations and impact on the healthcare system could still be significant due to the increased transmissibility of Omicron.

Spatial analysis of COVID-19 in North Minahasa Regency of North Sulawesi Province

Background: COVID-19 is an infectious disease that is currently a concern and has become a global problem. The trend in the number of confirmed cases and deaths due to COVID-19 every day is still increasing significantly. North Sulawesi Province currently has 7 regencies/cities which are declared as local transmission areas including North Minahasa Regency. The population density factor can affect the process of transmission of this disease. This study aims to determine the spatial description of the distribution of COVID-19 events in North Minahasa Regency.Methods: This quantitative research with descriptive observational design using a geographic information system approach. The location is in 10 sub-districts of North Minahasa Regency. Study population was all patients who were confirmed positive for COVID-19 based on data from the North Minahasa District Health Office as of 13 February 2021, as many as 1,273 cases. Simple random sampling was used and obtained 300 samples.Results: Results showed that the highest number of cases was for the age group 30-49 years (40%), female gender (54.7%), symptom onset date interval 4 days (26.7%), confirmation date grouped by month, namely October in 2020 (23%), the status of the patient recovered (86%), and there were no comorbidities (82%).Conclusions: Most of the cases of COVID-19 were found in densely populated areas and passenger transit areas between districts/cities. Policies on prevention and supervision of health protocols that are implemented must synergize across sectors and need to be improved.

Forecasting the onset date of southwest monsoon over Delhi

Using latest 32 years (1964-95) data, upper air temperatures and zonal and meridional components of winds of several selected stations for various standard isobaric levels (850 to 10 hPa) are screened for the pre-monsoon months of April & May in order to study their association with onset date of southwest monsoon at Delhi. Data for temperature and wind components for May for several stations exhibit significant correlations with onset-date. Some well known parameters presently in use in long range forecast models of monsoon seasonal rainfall have also been screened similarly. With a multiple regression technique, equations have been developed using suitable parameters from those which showed significant linear correlations.

Considerations for Improving Reporting and Analysis of Date-Based COVID-19 Surveillance Data by Public Health Agencies

More than a year after the first domestic COVID-19 cases, the United States does not have national standards for COVID-19 surveillance data analysis and public reporting. This has led to dramatic variations in surveillance practices among public health agencies, which analyze and present newly confirmed cases by a wide variety of dates. The choice of which date to use should be guided by a balance between interpretability and epidemiological relevance. Report date is easily interpretable, generally representative of outbreak trends, and available in surveillance data sets. These features make it a preferred date for public reporting and visualization of surveillance data, although it is not appropriate for epidemiological analyses of outbreak dynamics. Symptom onset date is better suited for such analyses because of its clinical and epidemiological relevance. However, using symptom onset for public reporting of new confirmed cases can cause confusion because reporting lags result in an artificial decline in recent cases. We hope this discussion is a starting point toward a more standardized approach to date-based surveillance. Such standardization could improve public comprehension, policymaking, and outbreak response. (Am J Public Health. 2021;111(12):2127–2132. https://doi.org/10.2105/AJPH.2021.306520 )

Relationship between monsoon onset over Thiruvananthapuram and Mumbai and rainfall over Kerala and Konkan

Lkkj & bl ’kks/k&Ik= esa nks LFkkuksa uker% fFk:ouUriqje vkSj eqEcbZ dk p;u djds ;g irk yxkus dk iz;kl fd;k x;k gS fd D;k ekulwu ds vkxeu dh rkjh[k dk Øze’k% dsjy vkSj dksad.k esa gksus okyh o"kkZ ds lkFk dksbZ laca/k gS A lewps ns’k ds fy, Hkkjrh; xzh"edkyhu ekulwu o"kkZ ¼vkbZ- ,l- ,e- vkj-½ ds lkFk ekulwu ds vkxeu dh rkjh[k ds laca/k dh Hkh tk¡p dh xbZ gS A bl v/;;u ds fy, 100 o"kksaZ ¼1901&2000½ ds vk¡dM+ksa dk mi;ksx fd;k x;k gS A fo’ys"k.k dh lgk;rk ls vk¡dM+ksa dh ,d:irk vkSj o"kkZ ds vU; y{k.kksa dh tk¡p dh xbZ gS A dsjy vkSj dksad.k esa vdky vkSj ekSle laca/kh ck<+ dh ledkfyd ?kVukvksa dh vko`fr dk irk yxk;k x;k gS vkSj mldh tk¡p dh xbZ gS A bl v/;;u ls ;g irk pyk gS fd ekulwu ds vkxeu ds laca/k esa fFk:ouUriqje vkSj eqEcbZ ds chp egRoiw.kZ laca/k gS A fFk:ouariqje vFkok eqEcbZ vkSj vkbZ- ,l- ,u- vkj- ds chp ekulwu ds vkxeu ds ckjs esa fdlh egRoiw.kZ laca/k dk irk ugha pyk gS A dsjy dh rqyuk eas dksad.k esa ekSle laca/kh ck<+ vf/kd vkrh gS A In this paper, choosing two locations viz., Thiruvananthapuram and Mumbai, an attempt has been made to find whether the onset date of monsoon has any bearing on monsoon rainfall over Kerala and Konkan respectively. Association of the onset dates with Indian Summer Monsoon Rainfall (ISMR) for the country as a whole has also been explored. The study utilizes 100 years’ (1901-2000) data. Homogeneity of the data and other rainfall features have been examined with the help of analysis. Frequency of simultaneous occurrence of droughts and meteorological floods at Kerala and Konkan have been determined and examined. The study showed that onset over Thiruvananthapuram and Mumbai are significantly related. It revealed absence of any significant relationship between onset over Thiruvananthapuram or Mumbai and the ISMR. Meteorological floods seem to be more frequent over Konkan compared to Kerala.

Interannual variability of the Arabian Sea warm pool intensity and its association with monsoon onset over Kerala

In this paper the relationships between the Arabian Sea warm pool intensity, Southern Oscillation (SO) and the monsoon onset have been discussed. The results show that the peak intensity of the warm pool in the Lakshadweep Sea is significantly correlated with the monsoon onset date over Kerala. Warmer Sea Surface Temperature (SST) anomalies in the warm pool region during April-May are associated with delayed monsoon onset over Kerala though the cause-and-effect relationship is not known. The Southern Oscillation Index (SOI) of March can provide predictive indications of the peak intensity of the warm pool which, normally occurs during April.