Anthropogenic aerosol effects on tropospheric circulation and sea surface temperature (1980–2020): separating the role of zonally asymmetric forcings

Anthropogenic aerosols (AAs) induce global and regional tropospheric circulation adjustments due to the radiative energy perturbations. The overall cooling effects of AA, which mask a portion of global warming, have been the subject of many studies but still have large uncertainty. The interhemispheric contrast in AA forcing has also been demonstrated to induce a major shift in atmospheric circulation. However, the zonal redistribution of AA emissions since start of the 20th century, with a notable decline in the Western Hemisphere (North America and Europe) and a continuous increase in the Eastern Hemisphere (South Asia and East Asia), has received less attention. Here we utilize four sets of single-model initial-condition large-ensemble simulations with various combinations of external forcings to quantify the radiative and circulation responses due to the spatial redistribution of AA forcing during 1980–2020. In particular, we focus on the distinct climate responses due to fossil-fuel-related (FF) aerosols emitted from the Western Hemisphere (WH) versus the Eastern Hemisphere (EH). The zonal (west to east) redistribution of FF aerosol emission since the 1980s leads to a weakening negative radiative forcing over the WH mid-to-high latitudes and an enhancing negative radiative forcing over the EH at lower latitudes. Overall, the FF aerosol leads to a northward shift of the Hadley cell and an equatorward shift of the Northern Hemisphere (NH) jet stream. Here, two sets of regional FF simulations (Fix_EastFF1920 and Fix_WestFF1920) are performed to separate the roles of zonally asymmetric aerosol forcings. We find that the WH aerosol forcing, located in the extratropics, dominates the northward shift of the Hadley cell by inducing an interhemispheric imbalance in radiative forcing. On the other hand, the EH aerosol forcing, located closer to the tropics, dominates the equatorward shift of the NH jet stream. The consistent relationship between the jet stream shift and the top-of-atmosphere net solar flux (FSNTOA) gradient suggests that the latter serves as a rule-of-thumb guidance for the expected shift of the NH jet stream. The surface effect of EH aerosol forcing (mainly from low- to midlatitudes) is confined more locally and only induces weak warming over the northeastern Pacific and North Atlantic. In contrast, the WH aerosol reduction leads to a large-scale warming over NH mid-to-high latitudes that largely offsets the cooling over the northeastern Pacific due to EH aerosols. The simulated competing roles of regional aerosol forcings in driving atmospheric circulation and surface temperature responses during the recent decades highlight the importance of considering zonally asymmetric forcings (west to east) and also their meridional locations within the NH (tropical vs. extratropical).

Mapping research on family business in tourism and hospitality: a bibliometric analysis

PurposeThis study aims to map the development of research on family business in tourism and hospitality and provides insights into the key contributors, key areas and current dynamics, and suggests future research directions in the field.Design/methodology/approachThis study uses the Web of Science (WoS) database to identify the 124 articles published in the theme. The study uses bibliometric indicators such as the co-citation network, word co-occurrence network to analyze the publication and citation structure using Science of Science (Sci2), OpenRefine, and Gephi.FindingsThe top authors, top journals and major themes are recognized using bibliometric techniques. The study identifies six keyword clusters: entrepreneurship, innovation, and empirical collaborating with tourism, hospitality, and family business. The country-wise collaboration indicates the lack of research in the eastern hemisphere of the world. The co-authorship shows studies shared among individuals of a few organizations. The trends from bibliographic coupling depict the evolution of research.Research limitations/implicationsThe scope of data collection for the network analysis is limited to the WoS. Incorporating papers from other databases might provide different network structures and insights.Originality/valueThe study is the first of its kind in the theme of family businesses in tourism and hospitality and will contribute to the literature by identifying future research directions.

Host-Adapted Strains of Spodoptera frugiperda Hold and Share a Core Microbial Community Across the Western Hemisphere

The fall armyworm Spodoptera frugiperda is an important polyphagous agricultural pest in the Western Hemisphere and currently invasive to countries of the Eastern Hemisphere. This species has two host-adapted strains named “rice” and “corn” strains. Our goal was to identify the occurrence of core members in the gut bacterial community of Fall armyworm larvae from distinct geographical distribution and/or host strain. We used next-generation sequencing to identify the microbial communities of S. frugiperda from corn fields in Brazil, Colombia, Mexico, Panama, Paraguay, and Peru, and rice fields from Panama. The larval gut microbiota of S. frugiperda larvae did not differ between the host strains neither was it affected by the geographical distribution of the populations investigated. Our findings provide additional support for Enterococcus and Pseudomonas as core members of the bacterial community associated with the larval gut of S. frugiperda, regardless of the site of collection or strain, suggesting that these bacteria may maintain true symbiotic relationships with the fall armyworm. Further investigations are required for a deeper understanding of the nature of this relationship.

Numerical Modeling of Ozone Loss in the Exceptional Arctic Stratosphere Winter–Spring of 2020

Dynamical processes and changes in the ozone layer in the Arctic stratosphere during the winter of 2019–2020 were analyzed using numerical experiments with a chemistry-transport model (CTM) and reanalysis data. The results of numerical calculations using CTM with Dynamic parameters specified from the Modern Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) reanalysis data, carried out according to several scenarios of accounting for the chemical destruction of ozone, demonstrated that both Dynamic and chemical processes contribute significantly to ozone changes over the selected World Ozone and Ultraviolet Radiation Data Centre network stations, both in the Eastern and in the Western hemispheres. Based on numerical experiments with the CTM, the specific Dynamic conditions of winter–spring 2019–2020 described a decrease in ozone up to 100 Dobson Units (DU) in the Eastern Hemisphere and over 150 DU in the Western Hemisphere. In this case, the photochemical destruction of ozone in both the Western and Eastern Hemispheres at a maximum was about 50 DU with peaks in April in the Eastern Hemisphere and in March and April in the Western Hemisphere. Heterogeneous activation of halogen gases on the surface of polar stratospheric clouds, on the one hand, led to a sharp increase in the destruction of ozone in chlorine and bromine catalytic cycles, and, on the other hand, decreased its destruction in nitrogen catalytic cycles. Analysis of wave activity using 3D Plumb fluxes showed that the enhancement of upward wave activity propagation in the middle of March over the Gulf of Alaska was observed during the development stage of the minor sudden stratospheric warming (SSW) event that led to displacement of the stratospheric polar vortex to the north of Canada and decrease of polar stratospheric clouds’ volume.

Review of Centroptella Braasch & Soldán 1980 (Ephemeroptera, Baetidae)

The Eastern Hemisphere genus Centroptella Braasch & Soldán 1980 (s. l.) is divided into three subgenera, the subgenus Centroptella s. str., the subgenus Crassolus Salles et al. 2016 and the subgenus Chopralla Waltz & McCafferty 1987. Among them, Centroptella s. str. and Crassolus are more closely related one to another than to Chopralla, that in the hierarchical nomenclature can be expressed as the following: Centroptella/g1 {Chopralla + Centroptella/g2 {Crassolus + Centroptella/g3}}. The subgenus Centroptella s. str. is distributed in the Oriental Region and Australia; it includes the following species: Centroptella (s. str.) longisetosa Braasch & Soldán 1980 with a new subspecies C. longisetosa cinerea subsp. n. (described here from southern India based on larvae, subimagines, imagines of both sexes and eggs associated by rearing); C. (s. str.) femorata sp. n. (described here from Lombok Island based on larva, subimago and male imago associated by rearing); C. (s. str.) soldani Müller-Liebenau 1983 (known from Sri Lanka and redescribed here based on larvae, female subimagines and eggs associated by rearing); C. (s. str.) ornatipes sp. n. (described here from southern India based on larvae, subimagines, imagines of both sexes and eggs associated by rearing); C. (s. str.) breviseta sp. n. (described here from New Guinea based on larvae, subimagines, female imagines and eggs associated by rearing); C. (s. str.) illiesi (Lugo-Ortiz & McCafferty 1998) (known from Australia and redescribed here based on non-reared larvae, subimagines and imagines); C. (s. str.) fustipalpus (Lugo-Ortiz & McCafferty 1998) (known from Australia as larvae only); C. (s. str.) quadrata Shi & Tong 2019 (known from China as larvae only); C. (s. str.) sp. cf. quadrata (reported here from Borneo based on male and female larvae ready to molt to subimago); C. (s. str.) ovata Shi & Tong 2019 (known from China as larvae only); and C. (s. str.?) papilionodes Marle et al. 2016 (known from Borneo as larvae only). The subgenus Crassolus is distributed in the Afrotropical Region, Oriental Region and southern Palaearctic Region; it includes the following species: Centroptella (Crassolus) inzingae (Crass 1947) (known from South Africa as larvae and imagines); C. (Crassolus) saxophila (Agnew 1961) (known from South Africa and redescribed here based on larvae, subimagines, imagines of both sexes and eggs associated by rearing); C. (Crassolus) ludmilae sp. n. (described here from Tanzania based on larvae, subimagines, imagines of both sexes and eggs associated by rearing), C. (Crassolus) ingridae Kluge et al. 2020 (known from Indochina and here redescribed based on larvae, subimagines, imagines of both sexes and eggs associated by rearing), C. (Crassolus) pontica (Sroka et al. 2019) (known from Turkey as larvae only); C. (Crassolus?) bifida (Shi & Tong 2019) (known from China as larvae only); C. (Crassolus?) sp. «Nepal» (reported here from Nepal based on larva. The subgenus Chopralla is distributed in the Oriental Region; it includes the following species: Centroptella (Chopralla) ceylonensis Müller-Liebenau 1983 (= C. similis Müller-Liebenau 1983 syn. n.) (known from southern India and Sri Lanka and redescribed here based on larvae, subimagines, imagines of both sexes and eggs associated by rearing); C. (Chopralla) ghatensis sp. n. (described here from southern India based on larvae, subimagines, imagines of both sexes and eggs associated by rearing); C. (Chopralla) rufostriata sp. n. (described here from Lombok Island based on larvae, subimagines, imagines of both sexes and eggs associated by rearing); C. (Chopralla) papuanica sp. n. (described here from New Guinea based on larvae, subimagines, female imagines and eggs associated by rearing); C. (Chopralla) pusilla Müller-Liebenau 1984 (known from Borneo and redescribed here based on male larvae ready to molt to subimago); C. (Chopralla) kangi sp. n. (described here from Borneo based on male and female larvae ready to molt to subimago); C. (Chopralla) colorata Soldán et al. 1987 [= C. fusina (Tong & Dudgeon 2003) syn. n.] (known from Vietnam and China as larvae and imagines associated by rearing); and C. (Chopralla) bintang Marle et al. 2016 (known from Borneo as larvae only).

A new, remarkable species of Platystethynium (Platypatasson) (Hymenoptera: Mymaridae) from New Zealand

Platystethynium (Platypatasson) earlyi Huber, sp. n. (Hymenoptera: Mymaridae), is described from both sexes reared from an egg of Rhaphidophoridae (Orthoptera) found in an old mining tunnel in New Zealand. The male is micropterous and has lateral ocelli but no median ocellus, a unique feature in Mymaridae found so far only in males of Platystethynium Ogloblin species. The remaining described Eastern Hemisphere species of Platystethynium are discussed and Platystethynium glabrum Jin & Li, syn. n., is placed in synonymy under P. onomarchicidum Ogloblin. A key to females, and males where known, of the described Eastern Hemisphere species of Platystethynium is given.

Dipole Pattern of Meridional Atmospheric Internal Energy Transport Across the Arctic Gate

High-latitude atmospheric meridional energy transport plays a fundamental role in the Arctic climate system. However, despite numerous studies, there are no established clear regional features of the atmospheric energy transport components from a large-scale perspective. This study aims at investigating the internal energy and its instantaneous sensible and latent heat transports in the troposphere through the Arctic gate at 70°N using the high-resolution climate reanalysis ERA5. We have done a regional analysis of the time series of heat fluxes across the zonal section and found by decomposing them into the empirical orthogonal functions that they have opposing features for the Eastern and Western Hemispheres. In particular, the sensible heat transport dominates in the Western Hemisphere, whereas the latent heat transport dominates in the Eastern Hemisphere. Moreover, we detected the existence of an anti-phase dipole pattern for each of these components in the entire troposphere, which is robust because it was retained during both the climate cooling in 1950–1978 and warming in 1979–2019. The hemispheric net fluxes indicate that the Arctic gains internal energy mostly due to the latent heat transport.

Seasonal and regional signatures of ENSO in upper tropospheric jet characteristics from reanalyses

The relationship of upper tropospheric jet variability to El Niño / Southern Oscillation (ENSO) in reanalysis datasets is analyzed for 1979–2018, revealing robust regional and seasonal variability. Tropical jets associated with monsoons and the Walker circulation are weaker and the zonal mean subtropical jet shifts equatorward in both hemispheres during El Niño, consistent with previous findings. Regional and seasonal variations are analyzed separately for subtropical and polar jets. The subtropical jet shifts poleward during El Niño over the NH eastern Pacific in DJF, and in some SH regions in MAMand SON. Subtropical jet altitudes increase during El Niño, with significant changes in the zonal mean in the NH and during summer/fall in the SH. Though zonal mean polar jet correlations with ENSO are rarely significant, robust regional/seasonal changes occur: The SH polar jet shifts equatorward during El Niño over Asia and the western Pacific in DJF, and poleward over the eastern Pacific in JJA and SON. Polar jets are weaker (stronger) during El Niño in the western (eastern) hemisphere, especially in the SH; conversely, subtropical jets are stronger (weaker) in the western (eastern) hemisphere during El Niño in winter and spring; these opposing changes, along with an anticorrelation between subtropical and polar jet windspeed, reinforce subtropical/polar jet strength differences during El Niño, and suggest ENSO-related covariability of the jets. ENSO-related jet latitude, altitude, and windspeed changes can reach 4(3)°, 0.6(0.3) km, and 6(3) ms−1, respectively, for the subtropical (polar) jets.

Baseline Susceptibility of Spodoptera frugiperda Populations Collected in India towards Different Chemical Classes of Insecticides

Fall armyworm (FAW), Spodoptera frugiperda, is a major pest of maize in the Americas and recently invaded the Eastern hemisphere. It was first detected in India in 2018 and is considered a major threat to maize production. FAW control largely relies on the application of chemical insecticides and transgenic crops expressing Bacillus thuringiensis insecticidal proteins. Assessing FAW resistance and insecticide susceptibility is a cornerstone to develop sustainable resistance management strategies. In this study, we conducted more than 400 bioassays to assess the efficacy of nine insecticides from seven mode-of-action classes against 47 FAW populations collected in 2019 and 2020 across various geographical areas in India. The resistance status of the field-collected populations was compared to an Indian population sampled in 2018, and an insecticide susceptible reference population collected in 2005 in Brazil. Low to moderate resistance levels were observed for thiodicarb, chlorpyriphos, deltamethrin, chlorantraniliprole and flubendiamide in several populations (including the reference population collected in 2018). The highest resistance ratios were observed for deltamethrin which likely compromises recommended label rates for pyrethroid insecticides in general. Our data provide a useful baseline for future FAW resistance monitoring initiatives and highlight the need to implement insecticide resistance management strategies.

Twenty-first century Southern Hemisphere impacts of ozone recovery and climate change from the stratosphere to the ocean

Changes in stratospheric ozone concentrations and increasing concentrations of greenhouse gases (GHGs) alter the temperature structure of the atmosphere and drive changes in the atmospheric and oceanic circulation. We systematically investigate the impacts of ozone recovery and increasing GHGs on the atmospheric and oceanic circulation in the Southern Hemisphere during the twenty-first century using a unique coupled ocean-atmosphere climate model with interactive ozone chemistry and enhanced oceanic resolution. We use the high emission scenario SSP5-8.5 for GHGs under which the springtime Antarctic total column ozone returns to 1980s levels by 2048 in our model, warming the lower stratosphere and strengthening the stratospheric westerly winds. Novel results of this study include the springtime stratospheric circulation response to GHGs, which is characterized by changes of opposing sign over the Eastern and Western Hemispheres, the opposing responses of the Agulhas leakage to ozone recovery and increasing GHGs, and large uncertainties in the prediction of atmospheric and oceanic circulation changes related to whether the ozone field is prescribed or calculated interactively. By performing a thorough spatial analysis of the predicted changes in the stratospheric dynamics, we find that the GHG effect during spring exhibits a strong dipole pattern, which contrasts the GHG effect during the rest of the year and which was previously not reported, as it cannot be detected when zonal means are considered. Over the Western Hemisphere, GHGs drive a warming of the lower stratosphere and a weakening of the westerlies, while over the Eastern Hemisphere they drive a cooling and a strengthening of the westerlies. Associated with these changes, planetary waves break higher up in the stratosphere over the Eastern Hemisphere, strengthening the polar downwelling and inducing dynamical warming in the upper stratosphere, while weakening the downwelling and inducing dynamical cooling in the lower stratosphere. The opposite occurs over the Western Hemisphere. Because the changes in the Western Hemisphere dominate during November in our model, we find that during this month GHGs lead to a weakening of the lower branch of the Brewer-Dobson Circulation, reinforcing the weakening caused by ozone recovery. At the surface, the westerly winds weaken and shift equatorward due to ozone recovery, driving a weak decrease in the transport of the Antarctic Circumpolar Current and in the Agulhas leakage, which transports warm and saline waters from the Indian into the Atlantic Ocean. The increasing GHGs drive changes in the opposite direction that overwhelm the ozone effect. The total changes at the surface and in the oceanic circulation are nevertheless weaker in the presence of ozone recovery than those induced by GHGs alone, highlighting the importance of the Montreal Protocol in mitigating some of the impacts of climate change. We additionally compare the combined effect of interactively calculated ozone recovery and increasing GHGs with their combined effect in an ensemble in which we prescribe the CMIP6 ozone field. This second ensemble simulates a weaker ozone effect in all the examined fields. The magnitude of the difference between the simulated changes at the surface and in the oceanic circulation in the two ensembles is as large as the ozone effect itself. This shows that the choice between prescribing or calculating the ozone field interactively can affect the prediction of changes not only in the atmospheric, but also in the oceanic circulation.