NAEA News, Volume 63, Number 3, June–July 2021

The Indian summer monsoon season (June to September) has been divided into two sub-seasons, viz., June + July (JJ) and August + September (AS). The performance of all-India AS rainfall has been examined when JJ rainfall is reported as being in excess/deficit, during the period 1871–2012. The study shows that the performance of AS rainfall is higher/lower than the JJ rainfall when JJ rainfall is in deficit/excess. The mean values of JJ and AS rainfalls are computed when JJ rainfall is in deficit/excess. The difference between the mean values is statistically significant. Sea surface temperature (SST) data over the Arabian Sea and Bay of Bengal for the period 1941–2011 have been used to examine the relationship between JJ SST and JJ, AS and AS − JJ (AS minus JJ) rainfalls. A statistically significant negative correlation is observed between JJ SST and JJ rainfall while significant positive correlation is observed between JJ SST and AS − JJ rainfall. The sub-seasonal relationship has been explained through the changes in the surface meridional temperature gradient over the Indian land and Oceanic regions in the JJ sub-season due to the performance of rainfall during the JJ sub-season. Wind data at 850 and 200 hPa levels for the period 1949–2012 have been analyzed to examine anomalies during deficit and excess JJ years. During deficit JJ rainfall years, easterly wind anomalies are observed at lower tropospheric levels over the Arabian Sea, which influence SST distributions. The SST distribution strengthens the meridional temperature gradient for developing the strong monsoon circulation during the AS sub-season thereby increasing the AS rainfall. A reverse situation is observed during excess JJ sub-seasons.

Effect of stocking time on yield and location of recapture in two forms of brown trout (Salmo trutta) when stocked in respect to migration activity

Impact of seasonality on the reproductive physiology of diploid and tetraploid eastern oyster, Crassostrea virginica

In their recent paper, Nigam and Bollasina [2010] (hereinafter NB) claimed to have found observational evidences that are at variance with the elevated heat pump (EHP) hypothesis regarding the possible impacts of absorbing aerosols on the South Asian summer monsoon [Lau et al., 2006; Lau and Kim, 2006]. We found NB's arguments and inferences against the EHP hypothesis flawed, stemming from their own out of context interpretation of the hypothesis. NB argued that the simultaneous negative correlation of aerosol with rainfall, and correlations with other quantities in May, are evidence against the EHP hypothesis. Their argument cannot be justified. First, Lau and Kim [2006] (hereinafter LK06) never stated that the main rainfall response to EHP is in May. Second, the EHP is about responses of the entire Indian monsoon system that are nonlocal in space and time with respect to the aerosol forcing. As shown in Figure 4 of LK06, while the aerosol anomalies are strongest in April-May, the strongest rainfall response is in June-July, with the enhanced rainfall fed by an induced thermally driven circulation which brings additional moisture from the ocean to the Indian subcontinent. Third, the increased rainfall over the Bay of Bengal as shown in Figure 1a of NB and the increased low-level convergence in Figure 1f of NB do not necessarily reflect responses associated with EHP but rather the large ]scale circulation that provides the buildup of the aerosols before the onset of the monsoon rainfall over India. Because aerosol can only accumulate where there is little or no washout by rain, the negative correlation is a necessary condition for increased atmospheric loading of aerosols. For the same reason, the spatial distributions of rainfall and aerosol generally are offset with each other, i.e., high aerosol in regions of low rainfall. This is evident in Figure 1, which shows the climatological mean of the MODIS aerosol optical depth (AOD), and TRMM rainfall over India in May. The maximum AOD is found over the Indo-Gangetic Plain and the desert regions of northwest India and Pakistan

ABSTRACTThe phytoplankton bloom magnitude (PBM) off the Yangtze River Estuary has important responses to the changes in the east–west position of the northwest Pacific subtropical high (NWPSH). The potential physical mechanism is analyzed through observations and a physical–biogeochemical model. Results reveal that the anomalously high precipitation in June–July increases the extension ranges of low salinity and high NO3 concentration water in NWPSH westward extension years. However, due to persistent cloudy and rainy weather, the light condition is unfavorable for the explosive growth of phytoplankton. When the NWPSH moves northward in August, the study area is controlled by anomalously anticyclonic circulation; hot and sunny weather prevails, the nutrients carried by the Yangtze River discharge during the previous June–July period continue to extend toward Jeju Island with the diluted water, favoring the explosive growth of phytoplankton, and vice versa. Sensitivity experiments reveal that when the June–July averaged river discharge and nutrients in NWPSH westward extension years are twice those in normal years, the range of phytoplankton blooms in August can extend to 124.2° E. When the June–July averaged river discharge and nutrients in NWPSH westward extension years are only 0.5 times those in normal years, the range of phytoplankton blooms in August only extends to 123° E. Therefore, the changes in river discharge and nutrient expansion range caused by the east–west position changes of the NWPSH in June–July are important reference indicators for phytoplankton bloom variations throughout the summer. The study provides new scientific reference for seasonal phytoplankton bloom forecasting off the Yangtze River Estuary.

A severe flooding hit southern China along the Yangtze River in summer 2020. The floods were induced by extreme rains, and the associated dynamic and thermodynamic conditions are investigated using daily gridded rainfall data of China and NCEP-NCAR reanalysis. It is found that the June–July rainfall over the Yangtze River Basin (YRB) experienced pronounced subseasonal variation in 2020, dominated by a quasi-biweekly oscillation (QBWO) mode. The southwestward-moving anomalous QBWO circulation was essentially the fluctuation of cold air mass related to the tropospheric polar vortex or trough-ridge activities over the mid-high latitude Eurasian in boreal summer. The southwestward-transport of cold air mass from mid-high latitudes and the northeastward-transport of warm and moist air by the strong anomalous anticyclone over the western North Pacific provided important large-scale circulation support for the extreme rainfall in the YRB. The analysis of streamfunction of water vapor flux demonstrates that a large amount of water vapor eastward zonal transport from the Bay of Bengal and Indo-China and northward transport from the South China Sea provided the background moisture supply for the rainfall. The quasi-biweekly anomalies of potential and divergent component of vertically integrated water vapor flux played an important role in maintaining the subseasonal variability of rainfall in June–July of 2020. The diagnosis of moisture tendency budget shows that the enhanced moisture closely related to the quasi-biweekly fluctuated rainfall was primarily attributed to the moisture convergence. Further analysis of time-scale decomposition in the moisture convergence indicates that the convergence of background mean specific humidity by the QBWO flow and convergence of QBWO specific humidity by the mean flow played dominant roles in contributing to the positive moisture tendency. In combination with adiabatic ascent over the YRB induced by the warm temperature advection, the boundary layer moisture convergence strengthened the upward transport of water vapor to moisten the middle troposphere, favoring the persistence of rainfall during June–July. The vertical moisture transport associated with boundary layer convergence was of critical importance in causing low-level tropospheric moistening. By comparison, the horizontal moisture advection played a secondary important role in the quasi-biweekly oscillation of rainfall in June–July 2020.

Seasonal, annual, and interannual variability in MLT quasi-two-day waves over the low-latitude region Kolhapur (16.8°N; 74.2°E)

The upper reaches of the Huai River in Central China are located in the East Asian monsoon region. Strong seasonality, as well as large interannual variability of rainfall, causes floods and an uneven supply of water. In order to conserve the water and mitigate the floods, dams and flood protection structures are constructed. Their design requires information about the rainfall. Daily observations from 1957 to 1986 from 78 rain gauges were used to study shape, orientation, movement and geographical and seasonal occurrence of storms in the 79 000 km2 study area. The rainfall characteristics were described using graphical plots, cross- and autocorrelation. Storms larger than 50 mm/day were found to occur from February to November, whereas storms exceeding 350 mm/day were confined to the main rainfall season from late June to mid-August. The southern part of the study area experienced a break in the rainfall season in late July, corresponding to the seasonal northward shift of the rain belt. A weekly periodicity of 7–8 days for rainfall was found during June–July, but not during August–September. During the whole period June–September, the spatial pattern of daily rainfall revealed an elongated shape, more pronounced during June–July than August–September. The rainfall area was orientated approximately from WSW to ENE during the whole period, and showed an anticlockwise rotation of about 16° per day during June–July. The cross-correlation analysis revealed that the rainfall area moved about 100 km/day eastward. These results and an investigation of meteorological maps indicate that the spatial correlation pattern of daily rainfall is produced by cold fronts on the Mei-Yu front. Suggestions are made as to how to use the results for the construction of design rainfalls in the study area. Copyright © 1999 John Wiley & Sons, Ltd.

This study investigated the characteristics of both the regular and irregular seasonal northward march of the East Asian summer wet environment (SNM_EASWE) over the continent during June–July over the past six decades and in the future. During 1961–2015 and in the future, the regular SNM_EASWE is defined mainly by an intensified climatic northward-moving rainband over eastern China, whereas the irregular SNM_EASWE is defined mainly by less clear features of northward-moving rainband. Further analyses indicate that the boreal summer intraseasonal oscillation (BSISO) played a dominant role in affecting the regular/irregular SNM_EASWE during 1961–79, whereas both the BSISO and the seasonally varying western North Pacific (WNP) eddy may exert notable influences on the regular/irregular SNM_EASWE during 1980–2015 and in the future, where the WNP eddy refers to the anomalous anticyclone/cyclone over the WNP associated with the anomalous western Pacific subtropical high. During 1980–2015, a La Niña–like (El Niño–like) condition in the tropical Pacific during June–July may induce a regular (irregular) SNM_EASWE case because of the influence of anomalous convection over the Maritime Continent on the seasonally varying WNP eddy; an anomalous warming (cooling) in the tropical Indian Ocean during June–July may also partly induce a regular (irregular) SNM_EASWE case via influencing the seasonally varying WNP eddy. The increased influence of the seasonally varying WNP eddy on the regular/irregular SNM_EASWE after 1979 is attributed to the increased interannual variability of convective activity over the Maritime Continent and of sea surface temperatures in the Arabian Sea after 1979.

Improvement in growth and yield attributes of cluster bean through optimization of sowing time and plant spacing under climate change scenario

Seasonal changes in surface ozone over South Korea

In this study we investigated the reproductive patterns and postnatal development in the tent‐making batArtibeus watsoni. We sampled two populations in the Golfito Wildlife Refuge and Corcovado National Park, south‐western Costa Rica, from June 2003 to March 2005. Most females were pregnant during the months of January and June, and most were lactating in March and July, indicating that this species exhibits seasonal bimodal polyoestry, with the first parturition peak occurring in February–March and the second in June–July. Additionally, we observed a postpartum oestrus following the first parturition, but not after the second. Females entered oestrus again in November–December and had a gestation period ofc. 3 months. A female‐biased sex ratio of neonates was observed during the second parturition period, and young were born at 32 and 56% of their mothers' body mass and length of forearm, respectively. Adult proportions in length of forearm were attained faster than adult proportions in body mass, and sustained flight was only possible after 35 days of age, when pups had achieved 100 and 80% of adult length of forearm and body mass proportions, respectively. Weaning and roosting independence occurred when young werec. 30–40 days old, and young females appeared to remain close to their place of birth, at least for their first mating period, whereas adult males were never recaptured near their birth site. In addition, sexual maturity was reached in as little as 3 months in females born during the first parturition period, whereas females born during the second birth period in June–July seemed to reach maturity at 6 months of age. Our results show thatA. watsonibelongs to the faster lane of the slow–fast continuum of life‐history variation in bats, which may be attributed primarily to its roosting and feeding ecology.

<h3>Summary</h3> <h3>Background</h3> Beginning in early February 2020, COVID-19 spread across the state of Georgia, leading to 258,354 cumulative cases as of August 25, 2020. The time scale of spreading (i.e., serial interval) and magnitude of spreading (i.e., <i>R</i>_<i>t</i> or reproduction number) for COVID-19, were observed to be heterogenous by demographic characteristics, region and time period. In this study, we examined the COVID-19 transmission in the state of Georgia, United States. <h3>Methods</h3> During February 1 to July 13, 2020, we identified 4080 transmission pairs using contact information from reports of COVID-19 cases from the Georgia Department of Public Health. We examined how various transmission characteristics were affected by disease symptoms, demographics (age, gender, and race), and time period (during shelter-in-place and after reopening). In addition, we estimated the time course of reproduction numbers during early February–mid-June for all 159 counties in the state of Georgia, using a total of 118,491 reported COVID-19 cases. <h3>Findings</h3> Over this period, the serial interval appeared to decrease from 5.97 days in February–April to 4.40 days in June–July. With regard to age, transmission was assortative and patterns of transmission changed over time. COVID-19 mainly spread from adults to all age groups; transmission among and between children and the elderly was found less frequently. Younger adults (20– 50 years old) were involved in the majority of transmissions occurring during or after reopening subsequent to the shelter-in-place period. By mid-July, two waves of COVID-19 transmission were apparent, separated by the shelter-in-place period in the state of Georgia. Counties around major cities and along interstate highways had more intense transmission. <h3>Interpretation</h3> The transmission of COVID-19 in the state of Georgia had been heterogeneous by area and changed over time. The shelter-in-place was not long enough to sufficiently suppress COVID-19 transmission in densely populated urban areas connected by major transportation links. Studying local transmission patterns may help in predicting and guiding states in prevention and control of COVID-19 according to population and region. <h3>Funding</h3> Emory COVID-19 Response Collaborative. <h3>Research in context</h3> <h3>Evidence before this study</h3> The ongoing COVID-19 pandemic has caused 37,109,581 cases and 1,070,355 deaths worldwide as of October 11, 2020. We searched PubMed for articles published on and before October 11, 2020 using keywords “novel coronavirus”, “SARS–nCoV–2”, “COVID-19”, “transmission”, “serial interval”, “reproduction number”, and “shelter-in-place”. Few published studies have estimated the serial interval but no study was found that examined the time-varying serial interval. Few studies have examined the transmission patterns between groups with different characteristics. And no study has examined the timevarying reproduction number for COVID-19 and impact of shelter-in-place order at the county level in the United States. <h3>Added value of this study</h3> To our knowledge, this is the first study showing the multiple aspects of COVID-19 transmission, including serial interval, transmission patterns between age, gender, or race groups, and spatiotemporal patterns, based on data from 118,491 confirmed COVID-19 cases and 4080 tracked pairs of infector and infectee. We found that during February–July the serial interval for symptom onset shortened, and the major contribution to the spread of COVID-19 shifted to younger ages (from 40–70 years old in February–April to 20–50 years old in June–July). We also found three to four weeks of the shelter-in-place slowed transmission but was insufficient to prevent transmission into urban and peri-urban counties connected with major transportation. <h3>Implications of all the available evidence</h3> The contracting serial intervals and increasing spread by younger generation show the COVID-19 transmission at county level changes over time. The spatiotemporal patterns of transmission in county level further provide important evidence to guide effective COVID-19 prevention and control measures (e.g., shelter-in-place) in different areas.

Over the South China Sea, the year‐to‐year variations in the intensity of the quasi‐biweekly (QBW) and 30–50‐day oscillations during June–July are anti‐correlated. An explanation is offered for the out‐of‐phase relationship. We found during strong QBW years, the June–July mean convection and easterly vertical shear are enhanced over the equatorial western‐central Pacific, with corresponding low‐level cyclonic meridional shear to the northwest. These conditions, concurring with the equatorial eastern Pacific warming, are favorable for emanation of moist Rossby waves from the equatorial western Pacific. On the other hand, the 30–50 day becomes active when the mean convection is enhanced over the eastern Indian Ocean and maritime continent where this mode stems from and develops, which often corresponds to cold western IO. One of these two large‐scale settings often occurs in the absence of the other, so that when one mode is strong during June–July the other mode tends to be weak.

Explanation of Corona Virus Control Novel by Warm and Humid Seasons in the World