World Meteorological Organization Research Articles

Toward effective communication of agrometeorological services

Abstract. Agrometeorological services are a subset of climate services targeted to support farmers' tactical and strategic decisions, with the potential to support farmers' capacity to cope with climate variability and change, as well as strengthen their resilience toward climatic risks. However, the effectiveness of such services is often limited by inadequate and unsuitable means of communication with farmers. Therefore, in recent years, the World Meteorological Organization (WMO) and partners have focussed their efforts on improving communication through these services. At the European Meteorological Society (EMS) Annual Meeting in September 2022, a workshop on effective communication of agrometeorological services was held as a hybrid side event, with the aim of answering the question: “How can we deliver efficient and effective agrometeorological services”? The workshop was a joint endeavour of Met Éireann, the International Society of Biometeorology, the EMS Media and Communication Committee, the Slovenian Environment Agency, the Slovenian Meteorological Society, and the S. W. Tromp Foundation. The aim of this workshop was to advance better communication of services to the agriculture sector as a basis for promoting adaptive strategies for weather and climate change, which would enable sufficient food production at present and in the future. The workshop also provided an opportunity for transdisciplinary discussions between national meteorological and hydrological services, universities, research institutes, private companies, and the WMO. The topics discussed at the workshop included learning about exemplar agrometeorological services at various national hydrometeorological services, strengthening communication of agrometeorological services to end-users, improving data and information sharing, and educating end-users. The workshop resulted in a list of recommendations for the future.

Improving global hydrological simulations through bias-correction and multi-model blending

There is an immediate need to develop accurate and reliable global hydrological forecasts in light of the future vulnerability to hydrological hazards and water scarcity under a changing climate. As a part of the World Meteorological Organization’s (WMO) Global Hydrological Status and Outlook System (HydroSOS) initiative, we investigated different approaches to blending multi-model simulations for developing holistic operational global forecasts. The ULYSSES (mULti-model hYdrological SeaSonal prEdictionS system) dataset, to be published as “Global seasonal forecasts and reforecasts of river discharge and related hydrological variables ensemble from four state-of-the-art land surface and hydrological models” is used in this study. The first step for improving these forecasts is to investigate ways to improve the model simulations, as global models are not calibrated for local conditions. The analysis was performed over 119 different catchments worldwide for the baseline period of 1981–2019 for three variables: evapotranspiration, surface soil moisture and streamflow. This study evaluated blending approaches with a performance metric based (weighted) averaging of the multi-model simulations, using the catchment’s Kling-Gupta Efficiency (KGE) for the variable to define the weight. Hydrological model simulations were also bias-corrected to improve the multi-model blending output. Weighted blending in conjunction with bias-correction provided the best improvement in performance for the catchments investigated. Applying modelled weights during blending original simulations improved performance over ungauged catchments. The results indicate that there is potential to successfully and easily implement the bias-corrected weighted blending approach to improve operational forecasts globally. This work can be used to improve water resources management and hydrological hazard mitigation, especially in data-sparse regions.

Evaluation of Statistical PMP Considering RCP Climate Change Scenarios in Republic of Korea

Extreme rainfall and floods have increased in frequency and severity in recent years, due to climate change and urbanization. Consequently, interest in estimating the probable maximum precipitation (PMP) has been burgeoning. The World Meteorological Organization (WMO) recommends two types of methods for calculating the PMP: hydrometeorological and statistical methods. This study proposes a modified Hershfield’s nomograph method and assesses the changes in PMP values based on the two representative concentration pathway (RCP4.5 and RCP8.5) scenarios in South Korea. To achieve the intended objective, five techniques were employed to compute statistical PMPs (SPMPs). Moreover, the most suitable statistical method was selected by comparing the calculated SPMP with the hydrometeorological PMP (HPMP), by applying statistical criteria. Accordingly, SPMPs from the five methods were compared with the HPMPs for the historical period of 2020 and the future period of 2100 for RCP 4.5 and 8.5 scenarios, respectively. The results confirmed that the SPMPs from the modified Hershfield’s nomograph showed the smallest MAE (mean absolute error), MAPE (mean absolute percentage error), and RMSE (root mean square error), which are the best results compared with the HPMP with an average SPMP/HPMP ratio of 0.988 for the 2020 historical period. In addition, Hershfield’s method with varying KM exhibits the worst results for both RCP scenarios, with SPMP/HPMP ratios of 0.377 for RCP4.5 and 0.304 for RCP8.5, respectively. On the contrary, the modified Hershfield’s nomograph was the most appropriate method for estimating the future SPMPs: the average ratios were 0.878 and 0.726 for the 2100 future period under the RCP 4.5 and 8.5 scenarios, respectively, in South Korea.

Climate, Weather Extremes and Health: Latest WHO-WMO Resources and Tools for Health Emergency Managers

Introduction:As populations worldwide are experiencing more frequent and intense weather and climate extremes, many professionals of the WADEM community are at the frontline of managing compounding and cascading impacts on physical and mental health. Vulnerable, isolated, and marginalized people are the most affected by climate and weather threats. The elderly and children faced 3.7 billion more life-threatening heatwave days in 2021 than annually in 1986-2005 increasing the need for emergency care on a large scale.Method:The World Health Organization (WHO) and World Meteorological Organization (WMO), together with partners from health agencies, climate services, academia and other sectors are collaborating to accelerate the use of climate, weather and environmental science and services for better health protection. A selection of key resources and tools will be highlighted that can be used by the WADEM community to better understand, anticipate, and manage health risks from extreme weather and climate.Results:Participants will learn about the new WHO-WMO ClimaHealth Portal, a global knowledge and action hub with huge potential for facilitating learning and action to better protect health from climate risks. Tools and resources include the Global Heat Health Information Network (GHHIN) Checklist and Technical Brief for improved heatwave preparedness and response in the context of COVID-19, and a new WHO Guidance Document on Measuring the Climate Resilience of Health Systems providing a framework and indicators for assessing and protecting health systems from climate threats.Conclusion:As extreme weather intensifies, integrated climate-informed services for the health sector including multi-hazard early warning systems and action plans, as well as strengthened partnerships between the health community and hydrometeorological services are indispensable to further restrict adverse health impacts. Accelerating the uptake and upscale of existing tools and resources is urgently needed to meet the increasing health and societal challenges caused by climate change and weather extremes.

Diverse skill of seasonal dynamical models in forecasting South Asian monsoon precipitation and the influence of ENSO and IOD

The South Asia Seasonal Climate Outlook Forum (SASCOF) issues seasonal tercile precipitation forecasts to provide advance warning of anomalously dry or wet monsoon seasons in South Asia. To increase objectivity of the SASCOF seasonal outlook, the World Meteorological Organisation recommends using a multi-model ensemble combining the most skilful dynamical seasonal models for the region. We assess the skill of 12 dynamical models at forecasting seasonal precipitation totals for 1993–2016 for the southwest (June–July–August–September) and northeast (October–November–December) monsoon seasons at regional and national levels for Afghanistan, Bangladesh, Nepal, and Pakistan, using identical forecast periods, hindcast initialisation months and domain used at the SASCOF. All models demonstrate positive skill when regionally-averaged, especially for the southwest monsoon season, noting considerable spatial differences. Models exhibit highest skill where correlation between observed precipitation and El Niño Southern Oscillation (ENSO) is highest, e.g., central/north India and Nepal during the southwest monsoon, and Afghanistan and north Pakistan during the northeast monsoon. Model skill is especially low in northwest India and northeast of South Asia during the southwest monsoon, e.g., Bangladesh (despite high precipitation totals) coinciding with a weak ENSO teleconnection. The Indian Ocean Dipole teleconnection is less pronounced in the southwest monsoon season, whereas the spatial pattern for the northeast monsoon closely resembles that of ENSO. Due to high variability in model skill, we recommend basing the SASCOF forecast on a multi-model ensemble of all models but discounting poorly performing models at the national level.

Effects of the Time Period Length on the Determination of Long-Term Mean Annual Discharge

Currently, the 40-year-long reference period 1961–2000 is used in Slovakia for systematic assessment of the hydrological regime. The World Meteorological Organization recommends unifying the climatic normal 1991–2020 with a reference period for hydrological characteristics for the purpose of climate change research. We have analyzed changes in the long-term mean annual discharges at 113 water-gauging stations over different time periods. Considering the history of the reference periods used in Slovakia, we have focused on the analysis of the 10, 20, 30, 40, and 50-year-long moving averages of the long-term mean annual discharges in the period 1961–2020 in comparison with the 1961–2000 reference period and the whole selected and analyzed period. The deviations of the annual flow rates for the area of Slovakia and river sub-basins have been analyzed. The results indicate that the new reference period to be used in Slovakia should include the time period after the year 2000. To determine its precise length, a more detailed analysis is needed.

Association of the corona virus (Covid-19) epidemic with environmental risk factors.

The current outbreak of the novel coronavirus SARS-CoV-2 (coronavirus disease 2019; previously 2019-nCoV), epicenter in Hubei Province (Wuhan), People's Republic of China, has spread too many other countries. The transmission of the corona virus occurs when people are in the incubation stage and do not have any symptoms. Therefore, the role of environmental factors such as temperature and wind speed becomes very important. The study of Acute Respiratory Syndrome (SARS) indicates that there is a significant relationship between temperature and virus transmission and three important factors, namely temperature, humidity and wind speed, cause SARS transmission. Daily data on the incidence and mortality of Covid-19 disease were collected from World Health Organization (WHO) website and World Meter website (WMW) for several major cities in Iran and the world. Data were collected from February 2020 to September 2021. Meteorological data including temperature, air pressure, wind speed, dew point and air quality index (AQI) index are extracted from the website of the World Meteorological Organization (WMO), The National Aeronautics and Space Administration (NASA) and the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Statistical analysis carried out for significance relationships. The correlation coefficient between the number of infected people in one day and the environmental variables in the countries was different from each other. The relationship between AQI and number of infected was significant in all cities. In Canberra, Madrid and Paris, a significant inverse relationship was observed between the number of infected people in one day and wind speed. There is a significant positive relationship between the number of infected people in a day and the dew point in the cities of Canberra, Wellington and Washington. The relationship between the number of infected people in one day and Pressure was significantly reversed in Madrid and Washington, but positive in Canberra, Brasilia, Paris and Wuhan. There was significant relationship between Dew point and prevalence. Wind speed showed a significant relationship in USA, Madrid and Paris. AQI was strongly associated with the prevalence of covid19. The purpose of this study is to investigate some environmental factors in the transmission of the corona virus.

Spatial and temporal variations of extreme climate index in the Songhua River Basin during 1961-2020.

Understanding climate change and extreme climate is of great significance for ensuring food security and socio-economic development of the Songhua River Basin. Based on the daily precipitation, maximum temperature and minimum temperature data during 1961-2020 from 69 meteorological stations in and around the Songhua River Basin, we analyzed the temporal and spatial variations of extreme temperature and precipitation in the Songhua River Basin using 27 extreme climate indices recommended by the World Meteorological Organization, and linear trend method, Mann-Kendall trend test and ordinary Kriging interpolation methodology. The results showed that, from 1961 to 2020, except for cold speel duration, the extreme cold index in the study area showed a downward trend, while the extreme warm index, extreme value index and other temperature indices showed an upward trend. The increasing trend of the minimum temperature was greater than that of the maximum temperature. Icing days, cold speel duration and warm speel duration showed an increasing trend from south to north, while the minimum value of maximum temperature and that of minimum temperature showed opposite spatial characteristics. The high value areas of summer days and tropical nights were mainly distributed in the southwestern region, while there was no obvious spatial variations of cool days, warm nights, and warm days. Overall, except for cold speel duration, other extreme cold indices had a rapid decreasing trend in the north and west of the Songhua River Basin. In the warm index, summer days, warm nights, warm days, and warm speel duration had a rapid upward trend in the north and west, and tropical nights had the fastest rise in the southwest. In the extreme value index, the maximum of temperature rose fastest in the northwest, while the minimum rose fastest in the northeast. Except for consecutive dry days, the rest of precipitation indices showed an increasing trend, and the fastest rising areas were mainly in the north-central part of the Nenjiang River Basin, while some areas in the south of the Nenjiang River Basin became dry. Heavy precipitation days, very heavy precipitation days, heaviest precipitation days, consecutive wet days, very wet day precipitation, extremely wet day precipitation, and annual precipitation showed a gradual decreasing pattern from southeast to northwest. Overall, the Songhua River Basin was warming and wetting, but there were some differences among different regions, especially the northern and southern parts of the Nenjiang River Basin.

A quarter century of WMO-Organized international cooperation in monsoon research : International Workshop on Monsoons

Over the last 25 years, the World Meteorological Organization through its Working Group on Tropical Meteorology Research carried out a major international collaboration effort to foster monsoon research and forecast centered around the series of International Workshops on Monsoons (IWM). This paper reviews the history of this activity and discusses its development and evolution that contributed significantly to the progress of monsoon research and forecast. Throughout this period the concept, scope and depth of monsoon research have all advanced considerably.

Correction of precipitation measurement for weighing precipitation gauges in a glacierized basin in the Tianshan Mountains

Precipitation is one of the most important climatological data for global hydrothermal cycle and climate change. The accuracy of precipitation data not only directly affects the hydrological processes, but also plays an important role in the climate and hydrology at regional and global scales. According to the in situ datasets, the precipitation measurement in automatic weather stations for Geonor T-200B was corrected by the World Meteorological Organization Solid Precipitation Intercomparison Experiment (WMO-SPICE) transfer functions. The parameters of transfer functions were tested and recalibrated by the local datasets. The results showed that the transfer functions showed better performance after recalibrating parameters by the local datasets. The root-mean-square error (RMSE) and mean bias decreased by an average of 34% and 42%, respectively. The corrected snowfall increased by 7% (14 mm) at the test station. Then, the new parameters were used in other automatic weather stations to correct precipitation, and it was found that solid precipitation was underestimated by 13% on the glacier surface affected by wind speed. Moreover, according to the corrected precipitation datasets observed in automatic weather stations and national meteorological stations, the precipitation–altitude relationship in the Urumqi River Basin was analyzed. The annual precipitation gradient was 115 mm km-1, and the maximum seasonal altitude occurred in summer with a value of 35 mm km-1 and in autumn with the lowest value of 1 mm km-1. When considering precipitation on the glacier surface, the yearly precipitation gradient was increased with the value of 158 mm km -1 in 2019.

Using portable low-resolution spectrometers to evaluate Total Carbon Column Observing Network (TCCON) biases in North America

Abstract. EM27/SUN devices are portable solar-viewing Fourier transform spectrometers (FTSs) that are being widely used to constrain measurements of greenhouse gas emissions and validate satellite trace gas measurements. On a 6-week-long campaign in the summer of 2018, four EM27/SUN devices were taken to five Total Carbon Column Observing Network (TCCON) stations in North America, to measure side by side, to better understand their durability, the accuracy and precision of retrievals from their trace gas measurements, and to constrain site-to-site bias among TCCON sites. We developed new EM27/SUN data products using both previous and current versions of the retrieval algorithm (GGG2014 and GGG2020) and used coincident AirCore measurements to tie the gas retrievals to the World Meteorological Organization (WMO) trace gas standard scales. We also derived air-mass-dependent correction factors for the EM27/SUN devices. Pairs of column-averaged dry-air mole fractions (denoted with an X) measured by the EM27/SUN devices remained consistent compared to each other during the entire campaign, with a 10 min averaged precision of 0.3 ppm (parts per million) for XCO2, 1.7 ppb (parts per billion) for XCH4, and 2.5 ppb for XCO. The maximum biases between TCCON stations were reduced in GGG2020 relative to GGG2014 from 1.3 to 0.5 ppm for XCO2 and from 5.4 to 4.3 ppb for XCH4 but increased for XCO from 2.2 to 6.1 ppb. The increased XCO biases in GGG2020 are driven by measurements at sites influenced by urban emissions (Caltech and the Armstrong Flight Research Center) where the priors overestimate surface CO. In addition, in 2020, one EM27/SUN instrument was sent to the Canadian Arctic TCCON station at Eureka, and side-by-side measurements were performed in March–July. In contrast to the other TCCON stations that showed an improvement in the biases with the newer version of GGG, the biases between Eureka's TCCON measurements and those from the EM27/SUN degraded with GGG2020, but this degradation was found to be caused by a temperature dependence in the EM27/SUN oxygen retrievals that is not apparent in the GGG2014 retrievals.

The role of WMO in the legal regulation of the use of modern technologies for processing meteorological data and forecasting

The author examines the activities of the international community in the field of climate and weather forecasting on the example of the activities of the World Meteorological Organization (WMO), whose members are more than 180 states, including the Russian Federation. The goals of this organization are determined, as well as the main activities to date, including the main projects in the field of climate forecasting. WMO projects such as "GROKO", WMO Information Systems included in strategic plans implemented by the organization within a period of 4 years are being considered. The interaction of WMO with Member States, as well as with other international organizations, for example, the International Civil Aviation Organization (ICAO), was considered. The author analyzes the activities of the WMO and examines the last World Meteorological Congress, held from May 22 to June 2. The key points that were put up for discussion are reviewed. Conclusions are drawn on the updated WMO policy, taking into account the statements made by the congress participants. The author also discusses the role of modern technologies in weather forecasting, as well as artificial intelligence (AI) in particular. Examples and possible legal problems of the use at the international level of various means of obtaining information about various climatic phenomena and natural disasters throughout the planet Earth are given.

Climate, Communities, and Capitalism: Critically Imagining and Co-Creating Pathways for a Sustainable Ireland

Climate, Communities, and Capitalism: Critically Imagining and Co-Creating Pathways for a Sustainable Ireland Amanda Slevin (bio) Wildfires, droughts, floods, beloved species facing extinction – a selection of stark indicators of the accelerating climate and ecological emergency. Underpinned by human patterns of production, consumption, and associated environmental degradation, the ‘triple planetary crises’1 of climate change, biodiversity loss, and pollution pose an existential threat to human and non-human species. Consequently, socio-ecological and scientific imperatives for urgent, transformative action have become firmly established, yet with only a few years to 2030 (a landmark year for climate commitments) our shared island, encompassing people on both sides of Ireland’s politically constructed border, is woefully unprepared to tackle the massive difficulties we collectively face. To move towards a genuinely sustainable future profound socioeconomic, ideological, political, and environmental transformations across all levels of every society are essential. Unsurprisingly, major challenges abound, not least the deeply embedded structures, ideologies, and practices fundamental to capitalism, which lie at the core of destructive society– environment interactions. Against this backdrop, it is useful to reflect upon conditions that influence why, how, and when a populace embarks on pathways for transformative change. Prospects for socio-ecological change encompass myriad dimensions and reinvigorate age-old debates around ‘agency’ and ‘structure’, prompting questions of who and/or what shapes human behaviour, as a central feature of transformative, multi-level action. Such deliberations are particularly apt in an era when many people across our island feel disempowered and are struggling, following wave after wave of turmoil, such as the costs of living, energy, and housing crises; consequences of the Covid-19 pandemic; war in Ukraine; ongoing legacies of Northern Ireland’s ethno-nationalist conflict; and Brexit. [End Page 61] Therefore, in this article, I contemplate how we might better respond to socio-ecological threats to enable our collective transition move towards a healthier and fairer future for all that share our island. As a critical interface between structure and agency, I posit ‘community’ as a vital element of societal transformations towards a more sustainable Ireland by 2030, and I explore how diverse communities affect bottom-up and top-down change. To set the scene, I examine mandates for climate action by enunciating pressing socioecological crises in the Anthropocene, the current geological epoch in which humans have become the primary drivers of changes to our planet. While I identify evolving top-down legal and policy frameworks that currently shape climate action, I argue that bottom-up grassroots approaches by communities are core for a sustainable world. Alongside empirical examples of community climate action, I explore diverse understandings of ‘community’, spanning psychological, philosophical, and physical dimensions of human interactions, and recognise the multiplicity of interpretations and forms of community that exist, not all of which are conducive to positive social change, as evident in Northern Ireland. Key questions arise within this inquiry: in the midst of a planetary emergency can ‘community’ act as an impetus to reimagine our shared future? Furthermore, can ‘community’ serve as a locus to regain human agency while acting as a driver for collective climate action across all levels of society? Offering a hopeful perspective, I articulate mechanisms to aid development of a ‘community of communities’ for climate action, including socio-eco-logical imagination, transformative teaching and learning, and sustainability praxis, all of which can be fostered within communities, universities, and wider society. These, in turn, can inform socio-eco-logical awareness, agency, and activism within and beyond diverse communities, enabling critical collective imagining and co-creation of pathways for a sustainable Ireland. I. Socio-ecological emergencies: ‘Code Red’ for Planet Earth Irrefutable scientific evidence by the Intergovernmental Panel on Climate Change (IPCC) and the World Meteorological Organization (WMO), among others, makes clear the ways in which our planet is experiencing an unprecedented climate catastrophe, driven by human activities.2 Anthropogenic (human-caused) climate change is defined as ‘a large-scale, long-term shift in the planet’s weather patterns and average temperatures’3 and is caused by burning fossil fuels like oil, gas, and coal; land-use change [End Page 62] such as cutting down forests; and farming livestock.4 Climate breakdown is part of the escalating planetary...

Assessment of Atmospheric and Oceanographic Measurements from an Autonomous Surface Vehicle

Abstract The present work details the measurement capabilities of Wave Glider autonomous surface vehicles (ASVs) for research-grade meteorology, wave, and current data. Methodologies for motion compensation are described and tested, including a correction technique to account for Doppler shifting of the wave signal. Wave Glider measurements are evaluated against observations obtained from World Meteorological Organization (WMO)-compliant moored buoy assets located off the coast of Southern California. The validation spans a range of field conditions and includes multiple deployments to assess the quality of vehicle-based observations. Results indicate that Wave Gliders can accurately measure wave spectral information, bulk wave parameters, water velocities, bulk winds, and other atmospheric variables with the application of appropriate motion compensation techniques. Measurement errors were found to be comparable to those from reference moored buoys and within WMO operational requirements. The findings of this study represent a step toward enabling the use of ASV-based data for the calibration and validation of remote observations and assimilation into forecast models.

The world meteorological organization Tenth International Workshop on tropical cyclones (IWTC-10): A summary

The Tenth International Workshop on Tropical Cyclones (IWTC-10) occurred from 5 to 9 December 2022 in Bali, Indonesia. This workshop continued the goal of the original IWTC, held in 1985 in Bangkok, Thailand, to bring together forecasters and researchers from countries around the world that are impacted by tropical cyclones (TCs) to discuss the latest research and forecast advances and share best practices to improve TC forecasts globally. The workshops have continued as a regular feature of WMO efforts to encourage the advancement of TC forecasting and improve ways of communicating TC hazards to the general public.Global TC forecasting efforts in the past 10–15 years have emphasized hazards and impacts of landfalling TCs beyond just track and intensity. Additionally, there has been a growing interest in improving the communication of these hazards and impacts, using concepts from social and behavioral sciences, in ways that can lead to effective decision-making from stakeholders (e.g., government officials, emergency managers, media, general public). As such, the theme for IWTC-10 was “Improved TC science and services for better decision-making.” More about this theme, how the workshop was structured around it, and key outcomes from the workshop are discussed in this summary article.

An Adaptive Method for the Estimation of Snow-Covered Fraction with Error Propagation for Applications from Local to Global Scales

Snow can cover over 50% of the landmass in the Northern Hemisphere and has been labelled as an Essential Climate Variable by the World Meteorological Organisation. Currently, continental and global snow cover extent is primarily monitored by optical satellite sensors. There are, however, no large-scale demonstrations for methods that (1) use all the spectral information that is measured by the satellite sensor, (2) estimate fractional snow and (3) provide a pixel-wise quantitative uncertainty estimate. This paper proposes a locally adaptive method for estimating the snow-covered fraction (SCF) per pixel from all the spectral reflective bands available at spaceborne sensors. In addition, a comprehensive procedure for root-mean-square error (RMSE) estimation through error propagation is given. The method adapts the SCF estimates for shaded areas from variable solar illumination conditions and accounts for different snow-free and snow-covered surfaces. To test and evaluate the algorithm, SCF maps were generated from Sentinel-2 MSI and Landsat 8 OLI data covering various mountain regions around the world. Subsequently, the SCF maps were validated with coincidentally acquired very-high-resolution satellite data from WorldView-2/3. This validation revealed a bias of 0.2% and an RMSE of 14.3%. The proposed method was additionally tested with Sentinel-3 SLSTR/OLCI, Suomi NPP VIIRS and Terra MODIS data. The SCF estimations from these satellite data are consistent (bias less than 2.2% SCF) despite their different spatial resolutions.

Importance of solar radiation and the need for improved respect to Sun by Agrometeorologists

Solar radiation refers to energy produced by the Sun, some of which reaches the Earth. This is the primary energy source for most processes in the atmosphere, hydrosphere, and biosphere. Solar radiation is of crucial importance inproviding the energy source for photosynthesis. During 1973 to 1977, when I did my Ph.D. in Agroclimatology in the Iowa State University, USA, I conducted the field experiments during 1975 and 1976 on soil-plant-water relations, growth and nutrient uptake patterns of field grown soybeans under water stress at the Western Iowa Experimental Farm, Castana. During these experiments, the solar radiation was measured with a pyranometer sensor mounted on an anodized aluminimum base. Daily solar radiation values were obtained from an LI-500 integrator attached to the pyranometer sensor. The attenuation of photosynthetically active radiation (PAR) and net radiation (NRAD) in the soybean canopy was determined during the growing season by using vertical profiles of radiation and leaf-area-index values. Once I received my Ph.D., I worked at the Headquarters of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in Hyderabad from 1977 to 1983 and at the ICRISAT Sahelian Center, Niamey, Niger from 1984 to 1996. In several field experiments in ICRISAT, the hourly values of net radiation were obtained through net radiometers mounted above the crop canopies. The growth and interception of PAR in a maize/pigeonpea intercrop and sole maize and sole pigeonpea crops grown in large plots were compared. The productivity of maize, sorghum, pigeonpea and a maize/pigeonpea intercrop in the operational research watersheds was measured in relation to the interception of PAR. In another study, it was shown that different shading ability of the crop canopies was one of the factors which determined the crop/weed competition balance and thus contributed to differential crop productivity observed in different cropping systems. Afterwards, when I worked at the World Meteorological Organization from 1996 to 2016 as the Chief of the Agricultural Meteorology Department, as the Director of the Climate Prediction and Adaptation Branch and as the Acting Secretary of the Intergovernmental Panel on Climate Change, a lot of work was done on Solar Radiation. Given all the above work on Solar Radiation, I emphasized the need for improved respect to Sun Bhagawan by Agrometeorologists at the end of this article.

The Challenges of Micro-Nowcasting and the Women’s Slope Style Event at the PyeongChang 2018 Olympic Winter Games

The Women’s Slope Style event of 11–12 February 2018 at the PyeongChang 2018 Olympic Winter Games posed considerable challenges to the competitors and decision-makers, requiring sub-kilometer and sub-minute weather predictions in complex terrain. The gusty wind conditions were unfair and unsafe as the competitors could not achieve sufficient speed to initiate or complete their jumps. The term micro-nowcasting is used here to reflect the extreme high-resolution nature of these science and service requirements. The World Meteorological Organization has conducted several research development and forecast demonstration projects to advance, accelerate and promote the art of nowcasting. Data from compact automatic weather stations, located along the field of play, reported every minute and were post-processed using time series, Hovmöller and wavelet transforms to succinctly present the information. The analyses revealed dominant frequencies of about 20 min, presumed to be associated with vortex shedding from the mountain ridges, but were unable to directly capture the gusts that affected the competitors. The systemic challenges from this and previous projects are reviewed. They include the lack of adequate scientific knowledge of microscale processes, gaps in modeling, the need for post-processing, forecast techniques, managing ever-changing service requirements and highlights the role of observations and the critical role of the forecaster. These challenges also apply to future high-resolution operational weather and warning services.

Fine-resolution analysis of the spatiotemporal characteristics of heatwaves in the Maloti-Drakensberg region, southern Africa: 1979–2021

Consistent with global patterns, heatwaves have increased in frequency, duration and intensity across southern Africa; under enhanced global warming this is projected to worsen. Heatwaves have many adverse impacts, but in biologically unique mountainous regions, like the Maloti-Drakensberg region, impacts on ecological processes and hydrological cycles are particularly dire given their highly sensitive nature. Despite this, extreme temperature changes and interannual variability patterns remain understudied in mountainous regions, owing largely to remoteness and inaccessibility. This is especially true for the Maloti-Drakensberg region. Hence, using heatwave indices developed by the World Meteorological Organization (WMO) Expert Team on Sector-Specific Climate Indices (ET-SCI), we explored spatiotemporal patterns for the seasonal average number, length and magnitude of summer (November-March) heatwaves for 1979/80–2020/21 using the AgERA5 reanalysis. Although higher elevation regions typically experienced more frequent, longer-lasting heatwave events with higher interannual variability levels, on average the Maloti-Drakensberg region experienced 1.4 heatwave events, lasting for 6.5 days with a magnitude of 3.5°C2. Interannually, the El Niño-Southern Oscillation influenced variability of heatwave characteristics, with positive (negative) heatwave number and length anomalies predominantly detected during El Niño (La Niña) phases, while for heatwave magnitudes no clear pattern was evident. These heatwave aspects were predominantly characterised by increasing trends, however, few regions exhibited statistically significant trends. Overall, trends averaged 0.003 events/year, 0.03 days/year and 0.02°C2/year for the mean number, length and magnitude of heatwaves, respectively. These results highlight that the Drakensberg-Maloti region is vulnerable to an increasing frequency, duration and magnitude of heatwaves, however, implications thereof require further study.

Analysis and Correction of Precipitation Observation Error in Henan Province

Accurate precipitation data is the basis for studying regional hydrological cycle and climate change, and correcting the precipitation observation error can effectively improve its accuracy. Therefore, based on the daily observation data (including snow and rain types) of 111 meteorological stations in Henan Province from 1960 to 2017, the precipitation observation error correction equation obtained from the precipitation error comparison observation experiment conducted in the Urumqi River Basin of China in the International Cooperation Project on Solid Precipitation Observation carried out by the World Meteorological Organization in 1980 was used to systematically correct the dynamic loss, wetness loss and trace loss of precipitation at 111 meteorological stations from 1960 to 2017. The main conclusions are: (1) The absolute error of each season decreases from south to north, the average absolute error in summer is the largest, 47.30mm, and the winter is the smallest; while the relative error is the opposite, the largest in winter and the smallest in summer. (2) The absolute error of the average annual precipitation in the entire region is above 60mm, gradually increasing from north to south, and the error in most areas is 70-160mm; The relative error varies little from region to region, and the error range is 10%-16%. (3) The average annual rainfall before the correction was 761.92mm, and the average annual rainfall after the correction was 881.1mm, and the corrected value was 119.18mm. There was a decreasing trend in rainfall before and after the correction from 1960 to 2017, but the trend of reduction in the revised rainfall series was greater than that in the measured series.