June October Research Articles

Estimates of marine turtle nesting populations in the south-west Indian Ocean indicate the importance of the Chagos Archipelago

AbstractGlobal marine turtle population assessments highlight the importance of the south-west Indian Ocean region, despite data gaps for the Chagos Archipelago. The archipelago hosts nesting hawksbill Eretmochelys imbricata and green turtles Chelonia mydas, both heavily exploited for 2 centuries until protection in 1968–1970. We assessed available nesting habitat and spatial distribution of nesting activity during rapid surveys of 90% of the archipelago's coastline in 1996, 1999, 2006 and 2016. We quantified seasonality and mean annual egg clutch production from monthly track counts during 2006–2018 along a 2.8 km index beach on Diego Garcia island. An estimated 56% (132 km) of coastline provided suitable nesting habitat. Diego Garcia and Peros Banhos atolls accounted for 90.4% of hawksbill and 70.4% of green turtle nesting. Hawksbill turtles showed distinct nesting peaks during October–February, and green turtles nested year-round with elevated activity during June–October. Estimates of 6,300 hawksbill and 20,500 green turtle clutches laid annually during 2011–2018 indicate that nesting on the Chagos Archipelago has increased 2–5 times for hawksbill turtles and 4–9 times for green turtles since 1996. Regional estimates indicate green turtles produce 10 times more egg clutches than hawksbill turtles, and the Chagos Archipelago accounts for 39–51% of an estimated 12,500–16,000 hawksbill and 14–20% of an estimated 104,000–143,500 green turtle clutches laid in the south-west Indian Ocean. The improved status may reflect > 40 years without significant exploitation. Long-term monitoring is needed to captureinterannual variation in nesting numbers and minimize uncertainty in population estimates.

Summertime Surface Wind Variability over Northeastern North America at Multidecadal to Centennial Time Scales via Statistical Downscaling

AbstractThe variability of the surface zonal and meridional wind components over northeastern North America during June–October is analyzed through a statistical downscaling (SD) approach that relates the main wind and large-scale circulation modes. An observational surface wind dataset of 525 sites over 1953–2010 provides the local information. Twelve global reanalyses provide the large-scale information. The large-to-local variability of the wind field can be explained, to a large extent, in terms of four coupled modes of circulation explaining a similar amount of variance. The SD method is mostly sensitive to the number of retained modes and subregionally to the large-scale information variable, but not to the reanalysis source. The SD methodological uncertainty based on the use of multiple configurations is directly related to the variability of the wind, similar in relative terms for both components. With an adequate choice of parameters the SD estimates provide more realistic variances than the reanalysis wind, although their correlations with respect to observations are lower than the latter. Additionally, while these different SD estimations are very similar on the reanalysis used, the various reanalysis wind fields show noticeable differences, especially in their variances. The wind variability is reconstructed back to 1850, making use of century-long reanalyses and two additional SLP gridded datasets, which allows estimating the variability at decadal to multidecadal time scales. Recent negative (significant) trends in the zonal component do not stand out in the multidecadal context, but they are consistent with a global stilling process, and are partially attributable to changes in the large-scale dynamics.

Length of Stay Children Hospitalized with Chronic Kidney Disease Based on Etiology and Stage in Dr. Hasan Sadikin Hospital Bandung

Objectives: This study aims to describe the LOS children hospitalized with CKD based on the etiology and stage at Dr. Hasan Sadikin General Hospital, Bandung in 2016–2018. Methods: This was a retrospective study with a cross-sectional design from June–October 2019. The inclusion were all medical records of pediatric inpatient diagnosed with CKD and exclusion criteria were incomplete medical record data and hospital readmission patients. The variables studied were CKD etiology, CKD stage, and length of stay Results: From 103 patients, the etiologies found were steroid-resistant nephrotic syndrome (SRNS) (58.25%), congenital anomalies of kidney and urinary tract (9.71%), urinary tract infection (5.83%), and chronic glomerulonephritis (21.36%). The mean LOS was 19 days. The longest LOS found in CKD stage 5 patients caused by SRNS (141 days). Meanwhile, the shortest LOS was found in CKD stage 2 patients caused by chronic glomerulonephritis and CKD stage 5 patients were caused by SRNS who died (1 day). Conclusion: Pediatric patients with CKD stage 5 with SRNS has the potential to have a longer LOS than other etiologies.

ФРГ В ИНФОРМАЦИОННОМ ОСВЕЩЕНИИ ЧЕХОСЛОВАЦКОГО КОНФЛИКТА 1968 ГОДА (ПО МАТЕРИАЛАМ СОВЕТСКИХ ГАЗЕТ)

The article discusses in detail the development of West Germany’s image in the Soviet press during the Czechoslovak conflict of 1968. The research is based on the materials of the main Soviet newspapers, as well as regional and city publications of the Sverdlovsk region. The chronological framework is June–October of 1968, the time of the highest intensity of the conflict and the large-scale Soviet propaganda campaign. The author uses both qualitative and quantitative methods of working with the sources. West Germany was perceived as the main enemy and emanated the main threat to Czechoslovakia and the entire socialist system. West Germany was seen in the Soviet press as having the most negative characteristics, as a key element of the «other world». In these conditions, the United States receded into the background. However, at the same time, the theme of cooperation between West Germany and the United States was used to strengthen the negative image of West Germany. The article analyzes the specifics of newspaper articles, and the vocabulary used by journalists. The transformation of the perception of West Germany during the escalating conflict is traced. The article discusses the use of historical subjects in depicting the activities of West Germany in relation to Czechoslovakia. The author characterizes the presentation of the «new Eastern policy» of West Germany in newspapers during the Czechoslovak crisis. The problem of using images to influence the audience is considered. Publications of official newspapers formed the basis of the majority of Soviet citizens’ knowledge about foreign policy. The importance of publications in establishing images of the outside world is stated.

Study of isotopic seasonality to assess the water source of proglacial stream in Chhota Shigri Glaciated Basin, Western Himalaya

AbstractThe impact of surface melt patterns and the Indian summer monsoon (ISM) is examined on the varying contributions of end member (snow, glacier ice, and rain) to proglacial streamflow during the ablation period (June–October) in the Chhota Shigri glaciated basin, Western Himalaya. Isotopic seasonality observed in the catchment precipitation was generally reflected in surface runoff (supraglacial melt and proglacial stream) and shows a shift in major water source during the melt season. Isotopically correlated (δ18O–δD) high deuterium intercept in the surface runoff suggests that westerly precipitation acts as the dominant source, augmenting the other snow‐ and ice‐melt sources in the region. The endmember contributions to the proglacial stream were quantified using a three‐component mixing. Overall, glacier ice melt is the major source of proglacial discharge. Snowmelt is the predominant source during the early ablation season (June) and the peak ISM period (August and September), whereas ice melt reaches a maximum in the peak melt period (July). The monthly contribution of rain is on the lower side and shows a steady rise and decline with onset and retreat of the monsoon. These results are persistent with the surface melt pattern observed in Chhota Shigri glacier, Upper Chandra basin. Moreover, the role of the ISM in Chhota Shigri glacier is unvarying to that observed in other glacierized catchments of Upper Ganga basin. Thus, this study augments the significant role of the ISM in glacier mass balance up to the boundary of the central‐western Himalayan glaciated region.

Controls on fine particle retention in experimental streams

The transport and retention of fine particulate organic matter (FPOM) in headwater streams plays a significant role in organic matter processing and represents a critical link between upstream and downstream systems. Benthic biofilms potentially alter substrate characteristics and dynamics. However, the influence of biofilm colonization on FPOM retention has not been well documented, likely due to inherent heterogeneity of natural systems. We expected that biofilm growth would either enhance or diminish FPOM retention in the streambed, whereas biofilm growth would vary depending on the underlying substrate template. We used a short-term FPOM addition technique to estimate transport distances of a fine particle analog (corn pollen: 70 μm) in four 50-m experimental streams (Q = 1.5 L/s) at the Notre Dame Linked Experimental Ecosystem Facility. Streams varied in substrate size (1-cm pea gravel vs 10-cm small cobble) and complexity (homogenous 50/50 mix vs alternating sections). We sampled streams on multiple dates over 5 mo (June–October) of biofilm colonization and senescence. While FPOM transport distances generally increased as biofilm colonization occurred, retention was variable across streams and over time. We found no consistent or simple pattern of FPOM retention in our streams. Rather, one of the strongest effects was an indirect relationship between FPOM removal and transient storage, a factor that is strongly driven by biofilm colonization. These results emphasize the dynamic feedback of the physical and biological environments influencing FPOM retention in streams.

FEASIBILITY OF A LOW-DOSE FRAILTY PREVENTION INTERVENTION AMONG OLDER AFRICAN AMERICANS

Older African Americans (OAA) are at high risk for becoming frail in later life. Interventions can reverse or delay frailty, yet OAA have largely been excluded from frailty intervention research. Many interventions are also time and resource intensive, making them inaccessible to socially disadvantaged OAA. We present results of a feasibility trial of a low dose frailty prevention intervention among 60 community-dwelling, pre-frail OAA aged 55+ recruited from a primary care clinic between June 1st and October 31st 2018. Using a 2-arm RCT, participants were assigned to the intervention, which was delivered by an occupational therapist (OT) and comprised of four sessions over four months (an OT evaluation, and sessions on healthy dietary practices, increasing physical activity, and maintaining a healthy lifestyle), or enhanced usual care (publicly available information about healthy lifestyle, home safety, and local elder services). Feasibility criteria were set a priori at 75% for participant retention (including attrition due to death/hospitalization), 80% for session engagement, 2 participants/week for mean participant accrual, and 90% for program satisfaction. Participants were 65% female with an average age of 76.58 years, 51.67% of which lived alone and 51.67% lived off of less than 15K per year. Feasibility metrics were met. The study recruited 2.5 participants per week and retained 75% of participants who attended 95% of scheduled sessions. Mean satisfaction scores were 93%. The intervention was feasible to deliver. Qualitative findings from exit interviews suggested changes to the program dose, structure, and content that could improve it for future use.

Mapping drought-induced changes in rice area in India

ABSTRACTRice is a staple food crop of India and is grown on 44 Mha (2011–12), 58.6% of which are irrigated. An inevitable phenomenon which looms over all aspects of human life and affects rice production in India is drought. Assessing drought damage using geospatial datasets available in the public domain, such as the Normalized Difference Vegetation Index (NDVI) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS), can provide specific and local ecoregion information for developing drought-resistant rice varieties. Based on multi-temporal NDVI data and field observations in 2009, we developed a methodology to identify and map drought-affected areas in India. A long-term (10-year) average of NDVI during the rainy (kharif) season (June–October) was compared with NDVI from a known drought year (2002–03) to identify changes in rice area. Rainfall data from the Tropical Rainfall Monitoring Mission (TRMM) was used to support the drought analysis. Spectral matching techniques were used to categorise the drought-affected rice areas into three classes – severe, moderate, and mild based on the intensity of damage assessed through field sampling. Based on these ground survey samples, spectral signatures were generated. It was found that the rice area was about 16% less in the drought year (2002–03) than in a normal year (2000–01). A comparison of the MODIS-derived rice area affected by drought in 2002 for each state and district against the difference in the kharif season harvested rice area between 2000 and 2002 (from official statistics) revealed a substantial difference in harvested area in 2002 that was largely attributable to drought. An 84.7% correlation was found between the MODIS-derived drought-affected area in 2002 and the reduction in harvested area from 2000–01 to 2002–03. Good spatial correlation was found between the drought-affected rice areas and reduction of rice harvested areas in different rice ecologies, indicating the usefulness of such geospatial datasets in assessing abiotic stress such as drought and its consequences.

A Climatological Satellite Assessment of Absorbing Carbonaceous Aerosols on a Global Scale

A global climatology of absorbing carbonaceous aerosols (ACA) for the period 2005–2015 is obtained by using satellite MODIS (Moderate Resolution Imaging Spectroradiometer)-Aqua and OMI (Ozone Monitoring Instrument)-Aura aerosol optical properties and by applying an algorithm. The algorithm determines the frequency of presence of ACA (black and brown carbon) over the globe at 1° × 1° pixel level and on a daily basis. The results of the algorithm indicate high frequencies of ACA (up to 19 days/month) over world regions with extended biomass burning, such as the tropical forests of southern and central Africa, South America and equatorial Asia, over savannas, cropland areas or boreal forests, as well as over urban and rural areas with intense anthropogenic activities, such as the eastern coast of China or the Indo-Gangetic plain. A clear seasonality of the frequency of occurrence of ACA is evident, with increased values during June–October over southern Africa, during July–November over South America, August–November over Indonesia, November–March over central Africa and November–April over southeastern Asia. The estimated seasonality of ACA is in line with the known annual patterns of worldwide biomass-burning emissions, while other features such as the export of carbonaceous aerosols from southern Africa to the southeastern Atlantic Ocean are also successfully reproduced by the algorithm. The results indicate a noticeable interannual variability and tendencies of ACA over specific world regions during 2005–2015, such as statistically significant increasing frequency of occurrence over southern Africa and eastern Asia.

Hepatitis B virus genotypes among chronic hepatitis B patients from Baghdad, Iraq and their impact on liver function

Hepatitis B virus (HBV) infection is a significant global health problem. Populations of different ethnicities show great heterogeneity in HBV genotype frequency distributions. A cross-sectional study was conducted during June–October 2018 to determine frequency of HBV genotypes among chronic HBV patients from Baghdad, Iraq. The method of detection was nested polymerase chain reaction system. Further, the study assessed the impact of HBV genotypes on serum level of liver-function tests: total serum bilirubin, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase. Eighty chronic HBV patients were enrolled in the study. Six HBV genotypes were identified (A, B, C, D, E and F). The most frequently encountered genotypes were B and F (72.5% each), while E genotype was the least observed with frequency of 12.5%. In addition, the majority of patients (77.5%) showed mixed HBV genotypes (two, three, four or five) with different genotypic combinations. Single HBV genotype patients represented only 17.5%. When patients positive for mixed HBV genotypes were inspected for serum level of liver-function parameters, only alkaline phosphatase showed a significant difference. It exhibited a gradual increase median that positively paralleled the number of positive genotypes; patients positive for one genotype showed the lowest median (87.0 U/L), while patients positive for five genotypes demonstrated the highest median (130 U/L). In conclusion, the HBV genotypes B and F were the most frequent among the investigated sample of Iraqi chronic HBV patients from Baghdad.

Egestion of plant propagules by turtles in a small Massachusetts river

ABSTRACTEvidence from flowing-water habitats has confirmed a role of turtles regarding the effective internal transport and viability of riparian plant seeds. We assessed potential propagule dispersal by Eastern painted turtles (Chrysemys picta) within a small river in Massachusetts and factors that may influence the diversity and abundance of egested propagules. From August–October 2015 and June–October 2016, we captured 69 turtles (28 male and 13 female), recorded standard measurements (sex, size, mass, BCI), and collected their faeces from which we isolated propagules. Propagules, mostly seeds, were observed in a small (28%) group of individuals. Overall, 4808 seeds of four taxa and 62 tubers were recovered. Most turtles (58%) defaecated propagules of just one taxon and number of seeds per turtle was highly variable (1–1506, 253.05 ± 414.55 seeds). Taxon richness, abundance, and Simpson Index of propagules varied significantly by sampling year. Sex-year interaction was also a significant predictor of propagule abundance. No turtle-specific features (sex or BCI) have any significant influence on any of the seeds egested. While our study suggests a minor role for C. picta as mobilisers of river plant propagules, these highly vagile animals may still create intermittent links between spatially isolated populations within and between waterbodies.

Benthic ctenophore (Order Platyctenida) reproduction, recruitment, and seasonality in south Florida

AbstractReproductive structures, modes, and seasonal patterns of size–class abundances are examined in two benthic platyctene (Family Coeloplanidae) ctenophore species present in dissimilar shallow marine environments in subtropical southeast Florida. Coeloplana waltoni, a minute (1–3 mm body length) epizoic associate of octocorals, occurs in exposed environments often under turbulent conditions, and Vallicula multiformis (2–10 mm) commonly occurs epiphytically on macroalgae in protected, calm‐water environments. Reproductive activity in C. waltoni is most active during the warm‐water summer season (June–October); gonadal development in V. multiformis occurs year‐round, and is most pronounced during sea‐warming periods in late spring (May) and late summer to early autumn (August–October), with release of cydippid larvae. Both species are hermaphroditic brooders, exhibiting paedogenesis (early gonadal development) at body lengths approximately one‐third (Coeloplana) to one‐sixth (Vallicula) of maximum adult size. Juvenile individuals (<0.6 mm) increased in abundance in C. waltoni during the summer reproductive period, and large (≥1 mm) pink‐colored individuals comprised 50% or more of samples from July through September. Seasonal abundance of gravid individuals and the timing of cydippid larval release in V. multiformis did not correspond closely with juvenile or adult population densities. Asexual fragmentation occurred in both ctenophore species, but was observed more frequently in individuals of V. multiformis. This asexual mode of reproduction probably accounted in part for the discordance between ctenophore abundances and larval recruitment events by sexual means. Morphological structures and behaviors associated with reproduction are described in this study. Uncommon images of reproductive products (gametes, embryos, larvae), spawning events, brooding, and asexual fragmentation are included, some for the first time in the published literature.

Impact of Zika Virus Emergence in French Guiana: A Large General Population Seroprevalence Survey.

BackgroundSince the identification of Zika virus (ZIKV) in Brazil in May 2015, the virus has spread throughout the Americas. However, ZIKV burden in the general population in affected countries remains unknown.MethodsWe conducted a general population survey in the different communities of French Guiana through individual interviews and serologic survey during June–October 2017. All serum samples were tested for anti-ZIKV immunoglobulin G antibodies using a recombinant antigen-based SGERPAxMap microsphere immunoassay, and some of them were further evaluated through anti-ZIKV microneutralization tests.ResultsThe overall seroprevalence was estimated at 23.3% (95% confidence interval [CI], 20.9%–25.9%) among 2697 participants, varying from 0% to 45.6% according to municipalities. ZIKV circulated in a large majority of French Guiana but not in the most isolated forest areas. The proportion of reported symptomatic Zika infection was estimated at 25.5% (95% CI, 20.3%–31.4%) in individuals who tested positive for ZIKV.ConclusionsThis study described a large-scale representative ZIKV seroprevalence study in South America from the recent 2015–2016 Zika epidemic. Our findings reveal that the majority of the population remains susceptible to ZIKV, which could potentially allow future reintroductions of the virus.

A space-time geostatistical model for probabilistic estimation of harmful algal bloom biomass and areal extent

Harmful algal blooms (HABs) have been increasing in intensity worldwide, including the western basin of Lake Erie. Substantial efforts have been made to track these blooms using in situ sampling and remote sensing. However, such measurements do not fully capture HAB spatial and temporal dynamics due to the limitations of discrete shipboard sampling over large areas and the effects of clouds and winds on remote sensing estimates. To address these limitations, we develop a space-time geostatistical modeling framework for estimating HAB intensity and extent using chlorophyll a data sampled during the HAB season (June–October) from 2008 to 2017 by five independent monitoring programs. Based on the Bayesian information criterion for model selection, trend variables explain bloom northerly and easterly expansion from Maumee Bay, wind effects over depth, and variability among sampling methods. Cross validation results demonstrate that space-time kriging explains over half of the variability in daily, location-specific chlorophyll observations, on average. Conditional simulations provide, for the first time, comprehensive estimates of overall bloom biomass (based on depth-integrated concentrations) and surface areal extent with quantified uncertainties. These new estimates are contrasted with previous Lake Erie HAB monitoring studies, and deviations among estimates are explored and discussed. Overall, results highlight the importance of maintaining sufficient monitoring coverage to capture bloom dynamics, as well as the benefits of the proposed approach for synthesizing data from multiple monitoring programs to improve estimation accuracy while reducing uncertainty.

Shortwave Spectral Radiative Signatures and Their Physical Controls

AbstractThe spectrum of reflected solar radiation emerging at the top of the atmosphere is rich with Earth system information. To identify spectral signatures in the reflected solar radiation and directly relate them to the underlying physical properties controlling their structure, over 90 000 solar reflectance spectra are computed over West Africa in 2010 using a fast radiation code employing the spectral characteristics of the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). Cluster analysis applied to the computed spectra reveals spectral signatures related to distinct surface properties, and cloud regimes distinguished by their spectral shortwave cloud radiative effect (SWCRE). The cloud regimes exhibit a diverse variety of mean broadband SWCREs, and offer an alternative approach to define cloud type for SWCRE applications that does not require any prior assumptions. The direct link between spectral signatures and distinct physical properties extracted from clustering remains robust between spatial scales of 1, 20, and 240 km, and presents an excellent opportunity to understand the underlying properties controlling real spectral reflectance observations. Observed SCIAMACHY spectra are assigned to the calculated spectral clusters, showing that cloud regimes are most frequent during the active West African monsoon season of June–October in 2010, and all cloud regimes have a higher frequency of occurrence during the active monsoon season of 2003 compared with the inactive monsoon season of 2004. Overall, the distinct underlying physical properties controlling spectral signatures show great promise for monitoring evolution of the Earth system directly from solar spectral reflectance observations.

A Narrative Review of the Literature on Insufficient Sleep, Insomnia, and Health Correlates in American Indian/Alaska Native Populations.

Insufficient sleep and insomnia promote chronic disease in the general population and may combine with social and economic factors to increase rates of chronic health conditions among AI/AN people. Given that insufficient sleep and insomnia can be addressed via behavioral interventions, it is critical to understand the prevalence and correlates of these disorders among AI/AN individuals in order to elucidate the mechanisms associated with health disparities and provide guidance for subsequent treatment research and practice. We reviewed the available literature on insufficient sleep and insomnia in the AI/AN population. PubMed, PsycINFO, Google Scholar, and ProQuest were searched between June 12th and October 28th of 2018. Prevalence of insufficient sleep ranged from 15% to 40%; insomnia prevalence ranged from 25% to 33%. Insufficient sleep was associated with unhealthy diet, low physical activity levels, higher BMI, worse self-reported health, increased risk for diabetes mellitus, cardiovascular disease, frequent mental distress, smoking, binge drinking, depression, and chronic pain. Insomnia was associated with depression, childhood abuse, PTSD, anxiety, alcohol use, low social support, and low trait-resilience levels. Research on evidence-based treatment and implementation practices targeting insufficient sleep and insomnia was lacking, and only one study described the development/validation of a measure of insufficient sleep among AI/AN people. There is a need for rigorous sleep research including testing and implementation of evidence-based treatment for insufficient sleep and insomnia in this population in an effort to help eliminate health disparities. We present recommendations for research and clinical practice based on the current review.

Seasonality in Intraseasonal Sea Surface Temperature Variability Along the Sumatra‐Java Southern Coast

AbstractThis paper evaluates the intraseasonal variability of sea surface temperature (SST) along the Sumatra‐Java southern coast using available satellite‐derived oceanic and atmospheric data combined with output from a numerical model. The result reveals that the intraseasonal variability of SST is greater during boreal summer–fall (June–October) than during boreal winter–spring (November–May). Composite analysis shows a correlation between positive/negative intraseasonal SST variabilities and coastal downwelling/upwelling, as well as onshore/offshore Ekman transport during summer–fall. During this period, with the significantly increasing role of oceanic advection, oceanic processes are evidently enhanced and dominate the intraseasonal variability of SST. Meanwhile, the contribution of atmospheric processes drops by 67%. During winter–spring, the intraseasonal SST is primarily contributed by atmospheric processes but has a nonsignificant relationship with sea level anomalies. Intraseasonal SST anomalies vary out of phase with surface wind anomalies. The result also shows a relatively small contribution by vertical processes throughout the year, with the maximum in April and the minimum during August–September. Further analysis reveals that the alternating dominance of atmospheric and oceanic processes on intraseasonal variability of SST is responsible for the seasonality along the Sumatra‐Java southern coast. Moreover, the result indicates that the seasonality in intraseasonal SST is different in the eastern Indonesian Seas, which tends to be relatively strong in boreal winter. Distinct dominance of atmospheric and oceanic processes in intraseasonal SST is the main reason for these differences in seasonal variation characteristics.

Dependence of Rainfall on Solar Activity Features

In the present paper, we have studied the statistical analysis between all India homogeneous rainfall (RF) with sunspot number (SN) during 1900-2014 (115-year period). We have calculated correlations coefficient of rainfall with sunspot number (SN) for annual and seasonal months: January, February (JF); March April May (MAM); June July August September (JJAS) and October November December (OND) and we have obtained high correlation ranging between 0.75 to 0.95. Our results show that rainfall is strongly influenced by sunspot number. Our study also indicates that occurrence of solar activity features play an important role for variability of rainfall.

Dependence of Rainfall on Solar Activity Features

In the present paper, we have studied the statistical analysis between all India homogeneous rainfall (RF) with sunspot number (SN) during 1900-2014 (115-year period). We have calculated correlations coefficient of rainfall with sunspot number (SN) for annual and seasonal months: January, February (JF); March April May (MAM); June July August September (JJAS) and October November December (OND) and we have obtained high correlation ranging between 0.75 to 0.95. Our results show that rainfall is strongly influenced by sunspot number. Our study also indicates that occurrence of solar activity features play an important role for variability of rainfall.

Tree-ring δ18O based PDSI reconstruction in the Mt. Tianmu region since 1618 AD and its connection to the East Asian summer monsoon

Abstract Previous studies on tree-ring stable oxygen isotopes (δ18O) in the monsoon region of China have rarely involved in variations of the East Asian summer monsoon (EASM) and its rainbelt. In this study, a tree-ring δ18O chronology of Cryptomeria fortune at Mt. Tianmu, located south of the Yangtze River lower reaches, was developed and applied to reconstruct the local June–October Palmer Drought Severity Index (PDSI6–10) during the 1618–2013 AD period. The reconstruction explains 40.5% of the observational PDSI6–10 variances during 1951–2013, captures the actual variation features at both high and low frequencies, largely represents the PDSI6–10 in the middle and lower reach regions of the Yangtze River and further south, and the reconstruction is well-compared with other existing proxies. The reconstruction reveals that the durations of 1620 s–1660 s, 1680 s–1700 s, 1810 s–1830 s, 1850 s, 1900 s–1940 s, and 1960 s were drought periods, while wet durations were 1730 s–1770 s, 1790 s–1800 s, 1860 s–1870 s, 1950 s, and 1980 s–1990 s. Based on the meteorological reanalysis data and new EASM definitions, the reconstructed PDSI6–10 correlates with the meiyu rainbelt precipitation and EASM intensity during May–June, which is when Mt. Tianmu is affected by the EASM rainbelt. The Mt. Tianmu tree-ring δ18O chronology exhibits significantly positive correlations with El Nino–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). The relationship of the tree-ring δ18O chronology with the PDO could be due to EASM associations, while it is not clear to explain the mechanism of ENSO connecting to the tree-ring oxygen isotope.