Main Season Research Articles

Challenges and resilience of an indigenous farming system during wartime (Tigray, North Ethiopia)

Due to war conditions, the local farmers had to largely rely on their own crop production, mainly by subsistence farming, in Tigray, North Ethiopia. We assessed the crop stands in 2021 and evaluated the level of resilience of the indigenous farming system. Quantitative data were collected from 161 farm parcels in various ecoregions of this tropical mountain region, in order to detect the share of sown land, crop types, and their status. This participatory monitoring was accompanied by semi-structured interviews. Farmers cultivated their farms late, left it uncultivated or marginally sowed oil crops as improved fallow (28%), due to lack of farming tools, oxen, fertilizer, seeds, or manpower. As compared to peace years, only few lands were sown with sorghum as there was active warfare in the sorghum planting period. The relatively good stands of wheat and barley (47%) are in line with the farmers’ priority given to cereals. Teff got a large land share because it could be sown up to the middle of the main rainy season and because farmers had consumed the seeds of their major cereal crops (wheat and barley) when hiding for warfare. Seeds left from consumption were only sown by late June, when troops had retreated, and the communities could revive. With almost no external support, the local farming system has proven to be remarkably resilient, relying on indigenous knowledge and local practices, block rotation, manure, improved fallow, changes in relative importance of crops, seed exchange, and support for one another. This is the first analysis of the socio-agronomic roots of the 2021–2022 Tigray hunger crisis, with a cereal harvest that could not at all sustain the local population as the planting season had been largely missed. The ability of the indigenous farming system to partially rebounce in times of autarky is another novel finding.

Contrasting coffee leaf rust epidemics between forest coffee and semi-forest coffee agroforestry systems in SW-Ethiopia

Ethiopian Arabica coffee is produced in different agroforestry systems which differ in forest management intensity. In forest coffee systems (FC), coffee shrubs grow naturally in the understory of Afromontane forests with little human intervention, whereas in semi-forest coffee systems (SFC) thinning of the canopy and removal of the understory is applied. Coffee leaf rust (CLR) disease is a growing concern for coffee agroforestry, but to what extent infection pressure is affected by management intensity is poorly known. Here we assessed CLR infection through time across FC and SFC systems in SW-Ethiopia. CLR infection was significantly higher for SFC, with a gradual reduction of this difference during the beginning of dry season (November) through main rainy season of (July). Our findings also demonstrated that CLR infections were significantly lower in the FC system as compared to SFC system in both years 2015/16 and 2020/21. The higher CLR infection was partly explained by lower crown cover and higher human impact. We expect that reduced wind speed and droplet penetration under closed canopies and reduced human-facilitated spore dispersal are the dominating mechanisms behind lower CLR infection in FC systems, yet lower coffee density in FC may also play a role. Overall, our results indicate that although higher management intensity still generally results in higher total yields per hectare, proportionally larger losses due to CLR infection can be expected. Therefore, introducing more coffee genetic diversity, screening resistant coffee varieties and increasing canopy cover in the SFC will mitigate the CLR disease pressure and guarantee the sustainability of higher yields of the system in the future. Also, lower yields in the FC will be rewarded through providing price premiums so that farmers instantly get a higher price for their lower yield, guaranteeing livelihoods.

The effect of catch crops in spring barley on nitrate leaching and their fertilizer replacement value

Catch crops have been proven effective in reducing nitrogen leaching in cropping systems due to their uptake of post-harvest soil mineral N prior to the main percolation season in winter. Information on the residual effect of catch crops, and their nitrogen fertilizer replacement value is scarce. To determine nitrogen fertilizer replacement values for different catch crops a field experiment was conducted over a four-year period on a sandy soil in Denmark, involving different catch crops and catch crop mixtures with non-legume and legume species. The residual effect of the catch crops was measured in spring barley grown in the residual year. For comparison, winter rye was also included. Over the four-year period the spring barley/fodder radish showed significantly lower leaching compared with the other catch crops, and the winter rye had the highest leaching. Regarding the residual effect, fodder radish and ryegrass, were most valuable, with nitrogen fertilizer replacement values ranging from 13 to 41 kg ha-1, based on fertilizer recovery efficiency of 50%. The process based APSIM (Agricultural Production Systems sIMulator) model was used to simulate the spring barley/catch crop rotations and the winter rye, and showed good model performance regarding N leaching and, crop yield and N uptake. The model was then run over a period of 20 years, to determine variations in N leaching and residual effects due to environmental conditions. The simulations showed that catch crops reduced N leaching by 38–64% when grown every year, and by 21–39% when grown only every second year. Nitrogen fertilizer replacement values ranged on average from 28 to 44 kg N ha-1, but showed high inter-annual variability. The nitrogen fertilizer replacement values showed only a weak relationship with the N uptake of the catch crop prior to termination, likely due to long term effects of N mineralisation from catch crop residues and pre-emptive competition for N by the catch crop.

Spatio-temporal changes of spring-summer dust AOD over the Eastern Mediterranean and the Middle East: Reversal of dust trends and associated meteorological effects

High dust concentrations in the Eastern Mediterranean - Middle East (EMME) region have serious effects on air quality, human health and climate. This study used long-term aerosol datasets during the main dusty season (April–July: AMJJ) over the EMME from 2000 to 2020, based on Moderate-Resolution Imaging Spectroradiometer (MODIS)/Terra-C6.1, Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2), and Copernicus Atmosphere Monitoring Service Reanalysis (CAMSRA) retrievals and analyzed the spatio-temporal variations and trends of dust, as well as the influencing factors. The dust aerosol optical depth (DAOD) experienced a significant upward trend during 2000–2010, followed by a significant decrease during 2010–2017. After 2017 and till 2020, the DAOD presented rather a stable trend. Aerosol Robotic Network (AERONET) data in the EMME region display trends compatible to those of both MERRA-2 and CAMSRA DAOD. The DAOD trends were linked to changes in regional meteorological parameters in the EMME. A significant downward trend in AMJJ sea-level pressure (SLP) during the early period (2000−2010) induced hot and dry winds from desert regions towards the EMME, which reduced relative humidity (RH) and raised temperature, thus favored soil drying and dust outbreaks through enhancing evaporation. In contrast, a significant increase in winter SLP during the late period (2010–2017), accompanying an increase in North Atlantic Oscillation index, induced cold, wet winds from northwest regions, which increased RH and lowered temperature, thus reducing dust loading in EMME. Positive anomalies in winter soil moisture persisted in the following AMJJ, and consequently suppressed dust activity. DAOD variability over the dust-prone regions was linked to various meteorological parameters via a multiple linear regression (MLR) model. The results show that climatic variability strongly affects the dust trends and contribute to better understanding of meteorological – dust dynamics in the EMME region.

What do monarchs feed on in winter? Nectar sources at hibernation sites

IntroductionThe steep population decline of the emblematic monarch butterfly is caused mainly by the reduction of food sources for caterpillars and adults, as well as disturbance in its overwintering forests. Although feeding at the overwintering sites in Mexico has long been considered unimportant, observations show that butterflies feed inside and outside of their forests on sunny days. Nectaring close to the hibernation colonies may be relevant for their conservation, as their reserves decline faster in disturbed forests. However, there are no systematic studies on nectar sources in the Monarch Butterfly Biosphere Reserve, Michoacán, Mexico.AimsIn this study, we identified and quantified the main plant species visited by butterflies for nectaring in the Reserve.MethodsWe collected systematic observational data on the flora and butterfly visits in three sanctuaries, around colonies formed between February and March of the 2019–2020 season.ResultsButterflies fed on 29 plant species from 10 families. Most had white, yellow or blue flowers, were somewhat synanthropic and had their main flowering season in winter. The most visited species were Salvia mexicana and S. plurispicata, which were also the most abundant. By individual plant, Prunus serotina, Crataegus mexicana, Buddleja sessiliflora, Verbesina oncophora and Roldana albonervia were the most visited.Discussion/Implications for insect conservationThe results point to possible interventions in support of the butterflies. The visited species are generally easy to encourage or cultivate and could be promoted in the surrounding agricultural areas.

Feasibility of condensate water recycle of split air handling unit in Chinese University buildings

Recycling the condensate water of the air conditioner could be explored as an alternative water source to contribute to building the green campus. This paper explored the condensate water production through actual measurement based on a split air handling unit (SAHU) in a university building. Then, the statistical analysis was used to analyze the recycling feasibility and the impact factors of the condensate water production in 31 Chinese provincial capital cities to obtain the recycling potential map of the condensate water generated from a SAHU. Results showed that: (1) In the measurement, the amount of condensate water produced by a single split air conditioner was 1.6 kg from 12:40 to 13:40. Therefore, the daily output of condensate water of the air conditioner with the university operation schedule could reach 52.99 kg during the main air-conditioning season. (2) Among the 31 provincial capital cities in China, the largest condensate water outputs could be found in the Hot Summer and Warm Winter zone and the Hot Summer and Cold Winter zone, with an average monthly output of 1600 kg and 1100 kg, respectively. (3) Regression analysis showed that the dry-bulb temperature and dew point temperature of outdoor air had the highest positive and significant influence on condensate water production. The objective of this study is to provide theoretical guidance for the design and energy conservation evaluation of the feasibility of SAHU condensate water recycling in universities.

Glacier runoff influences biogeochemistry and resource availability in coastal temperate rainforest streams: Implications for juvenile salmon growth

AbstractMeltwater contributions to watersheds are shrinking as glaciers disappear, altering the flow, temperature, and biogeochemistry of freshwaters. A potential consequence of this landscape change is that streamflow patterns within glacierized watersheds will become more homogenous, potentially altering the capacity of watersheds to support Pacific salmon. To assess heterogeneity in stream habitat quality for juvenile salmon in a watershed in the Alaska Coast Mountains, we collected organic matter and invertebrate drift and measured streamwater physical and biogeochemical properties over the main runoff season in two adjacent tributaries, one fed mainly by rain and the other partially by glacier ice/snowmelt. We then used bioenergetic modeling to evaluate how temporal patterns in water temperature and invertebrate drift in each tributary influence juvenile salmon growth potential. Across the study period, average invertebrate drift concentrations were similar in non‐glacierized Montana (0.33 mg m−3) and glacier‐influenced McGinnis Creeks (0.38 mg m−3). However, seasonal patterns of invertebrate drift were temporally asynchronous between the two streams. Invertebrate drift and modeled fish growth were generally higher in McGinnis Creek in the spring and Montana Creek in the Summer. For juvenile salmon, tracking these resource asynchronies by moving between tributaries resulted in 20% greater growth than could be obtained within either stream alone. These results suggest that hydrologic heterogeneity within watersheds may enhance the diversity of foraging and growth opportunities for mobile aquatic organisms, which may be essential for supporting productive and resilient natural salmon runs.

Phenotypic characterization and documentation of Gaddi dog of western Himalayan region of India

India has the privilege of having excellent dog populations, but efforts to recognize them as distinct breeds are far and wide. The present study was designed to undertake the phenotypic characterization of Gaddi dogs, in Himalayan region of the state of Himachal Pradesh, India. The approach used was to gather as much information available on Gaddi dogs from communities involved in their traditional rearing. Though, many anecdotal evidence about its origin exists, the most plausible relates it to the development of this distinct breed by Gaddi shepherds during migration in Himalayan ranges. The Gaddi dogs are predominately black with occasional white marking on the feet, tail, or trunk region. One of their main attributes is their massive, arched neck that protects them from predators. These dogs have harmonious build, medium stature, moderately long, robust muscular body. In bitches, age at first estrus ranged from 12-18 months with main breeding season from September to November. The number of whelping in a lifetime was reported to be 8-12 with a litter size of 4-8 pups. Shepherds usually do not follow a strict vaccination or deworming schedule of the dogs and housing is also not provided. The dog is primarily developed and used for the herding of sheep and goats by shepherds of the Gaddi tribe. These shepherds must be rewarded and encouraged to maintain the purity of the breed. The present study paved the way for recognition of the Gaddi dog and highlighted the headway options for its conservation and propagation.

Water Footprint of Rice Production in Malaysia: A Review of Evapotranspiration and Factors of Climate Change for Rice and Food Security in Malaysia

Rice is a special crop that requires a thin layer of water to produce, and is produced differently from other crops. The rice sectors in Malaysia continue to be developed in a proactive and progressive manner. Due to its growth process, rice has a different water footprint (WF) compared to other crops. This study improved the calculation of the blue and green WF of rice production and examined the variations of these footprints under the primary granary area of Malaysia. The effects of climate change will, however, make it more difficult to achieve food security and increase rice yields in the future. Therefore, this paper aims to discuss climate change impacts on rice production and food security in Malaysia. Many countries worldwide are becoming increasingly vulnerable to natural disasters due to climate change. Many climate models predict a decline in agricultural productivity due to excessive heat in tropical and subtropical regions, especially in Southeast Asia. Malaysia is no exception. Therefore, the present study examined the impact of climate change on rice yields in Muda Granary, Malaysia. Utilizing literature reviews, we assessed the value of evapotranspiration (ET) in order to calculate the green WF for the area. Climate variables (such as ET), yield, and variance of impact during the main season and off-season were the primary objectives of the study. Precipitation did not show a statistically significant difference between the main and off-seasons from 2011-2015. During the main crop season, the maximum ET was negatively associated with yield, but the minimum ET showed a positive association. In the off-season, green WF levels were higher than those in the main season. These findings indicate that climate change poses a serious threat to rice production, which will in turn affect food security as they are highly interconnected. Thus, it is high time for Malaysia to revamp its paddy and rice intervention strategies by giving due attention to enhancing the adaptive capacity of rice farmers to cope with climate change.

Changes in compound extremes of rainfall and temperature over West Africa using CMIP5 simulations

This study aims to characterize changes in compound extremes of rainfall and temperature over West Africa. For this purpose, data from CHIRPS observations, the ERA5 reanalysis, and twenty-four (24) climate models involved in the CMIP5 Project were analyzed. First, climate models were evaluated in terms of their capacity to simulate summer mean climatology and compound extremes during the historical period (1981–2005), and secondly, changes in compound extremes were examined under RCP8.5 emission scenario between the near future (2031–2055) and the far future (2071–2095) relative to the historical period. Despite the presence of some biases, the ensemble mean of the models well reproduces the compound extremes patterns over West Africa at the seasonal and intraseasonal timescales. The analysis over the historical period with CHIRPS/ERA5 dataset shows a strong occurrence of the dry/warm mode over the northern Sahel during the June-July-August-September period (JJAS; main rainy season) and over the Guinean region during the February-March-April-May season (FMAM; first and main rainy season). These strong occurrences are due to a weak and highly frequent precipitation recorded in these zones. The compound wet/warm mode is frequent in JJAS over the Sahel and the Sudanian zone (transition area between Sahel and Guinean regions), while in FMAM, its occurrence is maximum over the Guinean region. The study also shows that the dry/warm mode will increase in the whole Sahel (western and central) and in the Guinean zone in the near and far futures while the compound wet/warm mode will decrease in the whole region. This study suggests that the West Africa region will be prone to drought intensified by warmer temperatures and calls for climate action and adaptation strategies to mitigate the risks on rain-fed agriculture, energy, and on animals and human health.

Water Quality and Water Hyacinth Monitoring with the Sentinel-2A/B Satellites in Lake Tana (Ethiopia)

Human activities coupled with climate change impacts are becoming the main factors in decreasing inland surface water quantity and quality, leading to the disturbance of the aquatic ecological balance. Under such conditions, the introduction and proliferation of aquatic invasive alien species are more likely to occur. Hence, frequent surface water quality monitoring is required for aquatic ecosystem sustainability. The main objectives of the present study are to analyze the seasonal variation in the invasive plant species water hyacinth (Pontederia crassipes) and biogeochemical water quality parameters, i.e., chlorophyll-a (Chl-a) and total suspended matter (TSM), and to examine their relationship in Lake Tana (Ethiopia) during a one-year study period (2020). Sentinel-2A/B satellite images are used to monitor water hyacinth expansion and Chl-a and TSM concentrations in the water. The Case 2 Regional Coast Colour processor (C2RCC) is used for atmospheric and sunglint correction over inland waters, while the Sen2Cor atmospheric processor is used to calculate the normalized difference vegetation index (NDVI) for water hyacinth mapping. The water hyacinth cover and biomass are determined by NDVI values ranging from 0.60 to 0.95. A peak in cover and biomass is observed in October 2020, just a month after the peak of Chl-a (25.2 mg m−3) and TSM (62.5 g m−3) concentrations observed in September 2020 (end of the main rainy season). The influx of sediment and nutrient load from the upper catchment area during the rainy season could be most likely responsible for both Chl-a and TSM increased concentrations. This, in turn, created a fertile situation for water hyacinth proliferation in Lake Tana. Overall, the freely available Sentinel-2 satellite imagery and appropriate atmospheric correction processors are an emerging potent tool for inland water monitoring and management in large-scale regions under a global change scenario.

Reproductive Cycle and Sexual Group Maturity of Buccinum osagawai (Neogastropoda: Buccinidae)

This study was performed to obtain information on the basic reproductive ecology and biological resource management of Buccinum osagawai. Samples were collected from August 2018 to October 2019 with a drum-shaped net at a depth of 150–250 m along the continental shelf in Jumunjin, on the east coast of Korea. The species showed gonochorism and a lack of external sexual dimorphism. The overall sex ratio (F:M) was 1:1.2 (n = 549, F = 250, M = 299); as the size of the individuals increased, the proportion of males tended to decrease. The development pattern of the oocyte was synchronous, in which a dominant group of oocytes was identified within the same ovary. The size of the ripe oocyte was 82.3 (±22.6) × 125.5 (±22.0) μm. The spermatocyte development pattern was group-synchronous, in which multiple stages of germ cell populations were simultaneously identified within the same spermatogenic acinus. The gonad index (GI) for both males and females showed the highest value during June, after which it decreased sharply, and after August it was below 2.0. The main spawning season was from June to July, and the GI and stages of gonadal development did not show a pattern of seasonal changes. The main gonadal active season was from May to July, and both male and female gonadal development and maturation took place over a short period, whereas the recovery period after spawning was longer. At least 60.5% of the group, considering both males and females, showed maturity at 50.1 mm SH or more. Furthermore, the size of 50% group maturity was shown at approximately 50.0 mm SH.

English

Production of wheat in Ethiopia is under danger from wheat stem rust, which is brought on by the disease Puccinia graminis f.sp. tritici and has resulted in a yield loss of 100%. An investigation was conducted in a hotspot area (Debere Zeit, Ethiopia) to evaluate the status of Ethiopian durum wheat cultivars for their level of stem rust resistance in the field. During the main seasons of 2017, 2020, and 2021, 34 durum wheat varieties with three susceptibility checks were examined. Terminal Rust Severity (TRS), Coefficient of Infection (CI) and Area under Disease Progress Curve (AUDPC) were used to measure stem rust field resistance. Analysis of all disease parameters was carried out using R studio. Due to their low levels of AUDPC, ACI, and TRS values combined with MR infection type, two commercial varieties (Oda and Tob-66) may have a significant resistance gene(s) and seven varieties (Boohie, Kilinto, Ginchi, Robe, Toltu, Lelisso, and Bekelcha) showed a moderate level of field resistance with MR to MRMS responses and may have adult plant resistance mediated by minor resistance genes. Stem rust was found to affect 73.5% of the Ethiopian durum cultivars. Therefore, this study suggests that the national breeding effort should focus on local durum cultivars rather than the ones that were imported. Key words: Field resistance, durum wheat, stem rust, Puccinia graminis f.sp tritici.

Finding food in the hunger season: A mixed methods approach to understanding wild plant foods in relation to food security and dietary diversity in southeastern Madagascar

In many rural farming societies, wild plant foods (WPFs) continue to play an important role in everyday diets as well as in coping with hunger during food shortages. However, WPF collection and consumption may pose challenges to biodiversity conservation efforts (e.g., in protected areas), and some “famine foods,” foods not typically eaten under normal conditions, may have deleterious health impacts. Using data from a cross-sectional survey of 328 smallholder farmers and fisherfolk living in 15 villages surrounding Manombo Special Reserve on the southeastern coast of Madagascar, we examine the relationship between food security, dietary diversity, and consumption of WPFs, specifically giant aquatic arrowhead or via (Typhonodorum lindleyanum) and Polynesian arrowroot or tavolo (Tacca leontopetaloides), during the region's main lean season. We complement survey findings with focus group interviews to document traditional ecological knowledge and perceptions of these WPFs, including how tavolo and via are rendered edible, as well as human health effects from collecting, preparing, and eating them. Using multilevel logistic regression modeling, we found that consumption of these WPFs were significantly associated with inadequate nutrition among farmers. Wealthier households were less likely to consume these WPFs as a coping strategy during food insecure periods, while larger and more food insecure households were more likely to consume them. These findings reaffirm the importance of access to natural areas and support the design of protected area conservation strategies that honor local foodways and consider WPFs that serve as food safety nets for more vulnerable populations.

Performance Evaluation of Pigeon Pea (Cajanus cajan L. Millsp.) Variety for Registration in the Lowland Areas of Ethiopia

There were few released pigeon pea varieties in Ethiopia. This study was primarily conducted to diversify the availability of varieties, thus addressing socioeconomic cross-cutting issues. From eight pigeon pea genotypes after continuous evaluation, one variety, including the local check, was promoted with the objectives of evaluating the agronomic performance and registering a new variety in lowland areas of Ethiopia. The study was carried out during the main rain seasons of 2018-2019 to enhance pigeon pea productivity in the study area. A plot size of 10 meters by 10 meters was used in six locations. The spacing between rows and plants was 1.2 and 0.5 meters, respectively. Accordingly to the simple descriptive statistics, there were variabilities in the studied traits among the tested pigeon pea genotypes. The yield advantage of 39% was recorded for the test variety, Ashenafi (ICEAP00554), over the local check, which gave an opportunity to select the best-adapted material for the test and similar agroecologies. From the current study, an average yield of 1.83 t/ha was recorded across locations for a candidate variety, Ashenafi (ICP00554). The grain yield of the local cultivar had a mean of 1.04 t/ha. As a variety, Ashenafi (ICP00554) took the shortest duration to 75% flowering and 90% maturity (115 days and 171 days), respectively. In contrast, the local cultivar (Humbo local) took a long duration to 75% flowering and 90% maturity (164 days and 221 days), respectively. As a variety, Ashenafi (ICP00554) had superior performance over the local cultivar in terms of grain yield and earliness for flowering and maturity. Based on the overall performance, Ashenafi (ICP00554) was selected and registered. Therefore, this variety is recommended to popularize and thereby enhance pigeon pea production.

Spatio-temporal modeling of airborne pollen concentrations

Keywords: Pollen, Machine Learning, Allergic Disease Abstract Background and aim High concentrations of airborne pollen trigger seasonal allergies and possibly severe adverse respiratory and cardiovascular health events. Predicting pollen concentration accurately is valuable for epidemiological studies to determine the effects on cardiovascular, respiratory, and cognitive health. We aimed to develop a spatiotemporal land-use regression model for pollen, predicting daily concentrations at a fine spatial resolution of 1x1km across Switzerland between 2003 and 2020. Methods Daily pollen concentrations for hazel, alder, ash, birch, and grasses were available from 14 sites. We considered a range of spatial (elevation, tree type), temporal (date, season, month, week and day of the year, national daily pollen concentration) and spatiotemporal predictors (wind speed, wind direction, temperature, precipitation, relative humidity, satellite-observed Normalized Difference Vegetation Index (NDVI), and land-use (CLC, Landsat satellite) to explain variation in total pollen concentration for five specific pollen species. We applied a range of feature engineering techniques to encode categorical variables (land-use) and fill in missing values (Landsat). We applied a random forest model with 5-fold cross-validation. Results The median grass pollen concentration was 24 pollen/m3 (P5-P95 range 0-187 pollen/m3) during the main grass pollen season (May-July for all years). Preliminary results of a model predicting grass pollen concentration achieved an overall R2 of 0.74 and a root mean squared error (RMSE) of 24.12 pollen/m3 (cross-validation). Temperature, humidity, wind speed, NDVI, Landsat, average national daily pollen concentration and date features were the most important predictors for grass pollen concentration. Conclusions Building upon national observed pollen concentrations and using random forest machine learning, these spatiotemporal pollen models will serve to estimate individual residential pollen exposure. Resulting estimates will enable us to study respiratory and cardiovascular mortality and hospital admissions using historical data from the Swiss National Cohort and the Swiss Federal Office of Statistics.

Influence of meteorological factors on the dynamics of hazel, alder, birch and poplar pollen in the 2021 season in Kielce, Poland.

Hazel, alder, birch, and poplar pollen allergens are a common cause of pollen allergies. In a temperate climate, wind-pollinated plants are characterized by a seasonal pollen release cycle associated with the seasons of the year and weather conditions. Therefore, the aim of the present study was to assess the course of pollen seasons of some allergenic plants and to determine the effect of meteorological factors on the content of pollen grains in the bioaerosol in 2021 in Kielce, Poland. In relation to selected meteorological parameters, the length of the total and main pollen season, the sum of daily pollen grain concentrations in the season, the peak pollen concentration, and the number of days with values exceeding the species-specific threshold concentrations, were determined. Hazel and alder pollen were the first to appear in the air of Kielce. The longest pollen season was observed for birch, while hazel was characterized by the shortest season. The alder pollen release was intense, with the highest maximum concentration of pollen grains. The study revealed a significant influence of the maximum air temperature on the dynamics of hazel, alder and poplar pollen release. Birch pollen release was significantly correlated with the average air humidity. The concentration of alder and birch pollen grains also depended on rainfall intensity. The wind force had a significant impact on the pollen season of plants. There were various relationships between the meteorological factors and the content of pollen grains in the air. The wind speed and temperature had the greatest impact on plant pollen release, with birch and alder being particularly sensitive to weather conditions.

Asian Rice Calendar Dynamics Detected by Remote Sensing and Their Climate Drivers

Detecting crop calendar changes is critically important for crop monitoring and management, but the lack of annual, Asia-wide, and long-term rice calendar datasets limits our understanding of rice phenological changes and their climate drivers. In this study, we retrieved key rice phenological dates from the GLASS AVHRR LAI through combining threshold-based and inflection-based detection methods, analyzed the changes during the period 1995–2015, and identified the key climate drivers of the main rice seasons in Asia. The retrieved phenological dates had a high level of agreement with the referenced observations. All R2 were greater than 0.80. The length of the vegetation growing period (VGP) was mostly shortened (by an average of −4 days per decade), while the length of the reproductive growing period was mostly prolonged (by an average of 2 days per decade). Moreover, solar radiation had the most significant impact on the rice calendar changes, followed by the maximum and minimum temperatures. The VGP in tropical areas is the most sensitive to climate change. Our study extends the annual rice phenology dynamics to a higher spatial–temporal resolution and provides new insights into rice calendar changes and their climate drivers, which will assist governments and researchers regarding food security and agricultural sustainability.

Cloud forcing of surface energy balance from in situ measurements in diverse mountain glacier environments

Abstract. Clouds are an important component of the climate system, yet our understanding of how they directly and indirectly affect glacier melt in different climates is incomplete. Here we analyse high-quality datasets from 16 mountain glaciers in diverse climates around the globe to better understand how relationships between clouds and near-surface meteorology, radiation and surface energy balance vary. The seasonal cycle of cloud frequency varies markedly between mountain glacier sites. During the main melt season at each site, an increase in cloud cover is associated with increased vapour pressure and relative humidity, but relationships to wind speed are site specific. At colder sites (average near-surface air temperature in the melt season <0 ∘C), air temperature generally increases with increasing cloudiness, while for warmer sites (average near-surface air temperature in the melt season ≫0 ∘C), air temperature decreases with increasing cloudiness. At all sites, surface melt is more frequent in cloudy compared to clear-sky conditions. The proportion of melt from temperature-dependent energy fluxes (incoming longwave radiation, turbulent sensible heat and latent heat) also universally increases in cloudy conditions. However, cloud cover does not affect daily total melt in a universal way, with some sites showing increased melt energy during cloudy conditions and others decreased melt energy. The complex association of clouds with melt energy is not amenable to simple relationships due to many interacting physical processes (direct radiative forcing; surface albedo; and co-variance with temperature, humidity and wind) but is most closely related to the effect of clouds on net radiation. These results motivate the use of physics-based surface energy balance models for representing glacier–climate relationships in regional- and global-scale assessments of glacier response to climate change.

Influence of hydroclimatic variability on dengue incidence in a tropical dryland area

Dengue is an endemic disease in more than 100 countries, but there are few studies about the effects of hydroclimatic variability on dengue incidence (DI) in tropical dryland areas. This study investigates the association between hydroclimatic variability and DI (2008-2018) in a large tropical dryland area. The area studied comprehends seven municipalities with populations ranging from 32,879 to 2,545,419 inhabitants. First, the precipitation and temperature impacts on interannual and seasonal DI were investigated. Then, the monthly association between DI and hydroclimatic variables was analyzed using generalized least squares (GLS) regression. The model's capability to reproduce DI given the current hydroclimatic conditions and DI seasonality over the entire time period studied were assessed. No association between the interannual variation of precipitation and DI was found. However, seasonal variation of DI was shaped by precipitation and temperature. February-July was the main dengue season period. A precipitation threshold, usually above 100 mm, triggers the rapid DI rising. Precipitation and minimum air temperature were the main explanatory variables. A two-month-lagged predictor was relevant for modeling, occurring in all regressions, followed by a non-lagged predictor. The climate predictors differed among the regression models, revealing the high spatial DI variability driven by hydroclimatic variability. GLS regressions were able to reproduce the beginning, development, and end of the dengue season, although we found underestimation of DI peaks and overestimation of low DI. These model limitations are not an issue for climate change impact assessment on DI at the municipality scale since historical DI seasonality was well simulated. However, they may not allow seasonal DI forecasting for some municipalities. These findings may help not only public health policies in the studied municipalities but also have the potential to be reproducible for other dryland regions with similar data availability.