Maritime Background Research Articles

MLANet: A Robust Ship Segmentation Network Based on Multilevel Multiattention Feature Fusion for Complex Maritime Background Environments

MLANet: A Robust Ship Segmentation Network Based on Multilevel Multiattention Feature Fusion for Complex Maritime Background Environments

Histoire et culture maritimes en Indonésie : mise en œuvre dans l’apprentissage des études sociales

This research explores the integration of Indonesia's maritime history and culture into Social Studies education. Indonesia, as the world's largest archipelagic nation, possesses a rich maritime heritage and diverse culture that significantly shape national identity and promote sustainable economic development. The study delves into Indonesia's historical maritime background, including its pivotal role in global trade routes and cultural development. It encompasses maritime kingdoms like Srivijaya, Majapahit, and Makassar as well as the influences of China, India, and the Arab world on maritime culture and trade. The article highlights Indonesia's maritime cultural traditions, fostering appreciation for cultural diversity, environmental sustainability, and responsible attitudes towards marine resources. Various methods, including field research, multimedia resources, and interdisciplinary collaborations, can be employed to implement Indonesia's maritime history and culture into IPS education. This integration enables students to develop a holistic understanding of society, economy, and marine environments. By incorporating Indonesia's maritime heritage, students gain an understanding of marine conservation and sustainable economies, while embracing local wisdom applicable to their daily lives. Ultimately, this implementation fosters a generation that values marine environments, respects cultural diversity, and contributes to sustainable development, providing a solid foundation for understanding history, culture, and the significance of maritime affairs in Indonesia. Keywords: maritime history, maritime culture, social studies, sustainability

Ensemble learning-based method for maritime background subtraction in open sea environments

Maritime autonomous surface ships employ computer vision to detect open sea environments for various applications, including safety surveillance, collision prevention, and autonomous navigation, all of which have grown increasingly important as maritime traffic has increased and automated systems have become more prevalent. Background subtraction (BS) may be used for real-time change detection in unseen contexts to obtain foreground information of interest without prior knowledge and training. However, because marine settings are dynamic, classic BS methods are vulnerable to noise (e.g., reflections and ship wakes) on the ocean surface. As a result, developing effective background models is challenging, resulting in considerable false foreground information. This study proposes a novel maritime BS method based on ensemble learning theory that integrates heterogeneous BS methods. Maritime noise filtering is also included to increase the background model’s ability to cope with complex marine situations. Experimental comparisons conducted on the Maritime BS Benchmark dataset showed that the proposed method had the highest real-time detection accuracy. The proposed method may also be used to improve autonomous ships’ situational awareness abilities in open waters, enhancing maritime transportation security.

Vertical profile of culturable bacteria from the Makassar Strait, Indonesia

Abstract. Siallagan ZL, Kristianti T, Dwivany FM, Nugrahapraja H, Fretes CED, Fadli M, Trinugroho JP, Radjasa OK, Susanto RD. 2023. Vertical profile of culturable bacteria from the Makassar Strait, Indonesia. Biodiversitas 24: 1356-1365. Indonesia's extensive maritime background is a rich biological and chemical diversity source. This diversity has become as source of unique chemical compounds with the potential for industrial development as enzymes, molecular probes, chemicals, pharmaceuticals, cosmetics, nutritional supplements, and agrochemicals. The present study aimed to analyze the community composition of culturable bacteria from three different layers of depth from Makassar Strait using high throughput DNA Illumina sequencing of 16S rRNA. Bioinformatic analysis has rendered 140336 high-quality sequences with an average of 124127 sequences per sample and a mean read length of 428 bp. Results showed that Firmicutes and Proteobacteria were the two most abundant phyla. Taxonomic analysis showed that Firmicutes dominated all samples. Genus Streptomycetes and Psychrobacter occurred mainly in the culture from the surface layer. Species richness and diversity for the bacterial communities at 100 m were higher than those at 5 m and 200 m. PCA plot, NMDS plot, and UPGMA clustering demonstrated that the culturable bacterial community compositions of 100 and 200 ms were highly similar and distinct from those in 5 m. This research discovered microbes with potential as sources of marine natural products, including Streptomyces, Paenibacillus, Bacillus, Psychrobacter, Arthrobacter, Bradyrhizobium, Gemmatimonas, and Acidobacteria.

Factors Controlling the Diversities of MJO Propagation and Intensity

AbstractThe diversity of the Madden-Julian Oscillation (MJO) in terms of its maximum intensity, zonal extent and phase speed was explored using a cluster analysis method. The zonal extent is found to be significantly correlated to the phase speed. A longer zonal extent is often associated with a faster phase speed.The diversities of zonal extent and speed are connected with distinctive interannual sea surface temperature anomaly (SSTA) distributions and associated moisture and circulation patterns over the equatorial Pacific. An El Niño–like background SSTA leads to enhanced precipitation over the central Pacific, allowing a stronger vertically overturning circulation to the east of the MJO. This promotes both a larger east-west asymmetry of column-integrated moist static energy (MSE) tendency and a greater boundary-layer moisture leading, serving as potential causes of the faster phase speed. The El Niño–like SSTA also favors the MJOs intruding further into the Pacific, causing a larger zonal extent.The intensity diversity is associated with the interannual SSTA over the Maritime Continent and background moisture condition over the tropical Indian Ocean. An observed warm SSTA over the Maritime Continent excites a local Walker cell with a subsidence over the Indian Ocean, which could decrease the background moisture, weakening the MJO intensity. The intensity difference between strong and weak events would be amplified due to distinct intensity growth speed. The faster intensity growth of a strong MJO is attributed to a greater longwave radiative heating and a greater surface latent heat flux, as both of which contribute to a greater total time change rate of the column-integrated MSE.

Infrared maritime dim small target detection based on spatiotemporal cues and directional morphological filtering

The existing small target detection algorithms will suffer severe performance deterioration when the weak target is submerged in heavy cluttered infrared (IR) maritime image. To settle this problem, a small target detection scheme is developed based on spatiotemporal cues and multidirectional morphological filtering. Initially, considering the small target will be isotropic because of the point spread function of the long-distance thermal imaging, while background edge clutters are generally local directional, the multidirectional structuring elements (MSEs) are constructed. By incorporating constructed MSEs and morphological operations, the directional morphological filtering (DMF) is established to measure the multidirectional differences between target region and local surroundings. Then, according to the brightness and isotropic Gaussian-like shape of small target in local spatial domain, the local intensity difference measure (LIDM) and the local Gaussian-like shape measure (LGSM) are presented to differentiate the small target from background clutters. After that, in order to integrate the two spatial properties, the multidirectional improved top-hat filter (MITHF) is proposed by fusing LIDM and LGSM to highlight potential small targets and suppress strong structural edge clutters. Finally, considering the consistency of targets and the fluctuation of sea clutters in temporal domain, a new appearance descriptor namely histogram of oriented morphological filtering (HOMF) is designed to characterize the small target by fully exploiting the advantages of DMF, and the HOMF-based multi-frame confirmation strategy (HMCS) is developed to further identify real small targets and eliminate false alarms. Extensive experiments prove that proposed algorithm is superior to the compared methods, especially for dim small target buried in intricate maritime background clutter.

Unexpected seasonal variations and high levels of ozone observed at the summit of Nanling Mountains: Impact of Asian monsoon on southern China

Five-year continuous O3 measurements were conducted for the first time at the summit of Nanling Mountains (112.88° E, 24.68° N, 1690 m a.s.l), southern China in 2013–2017. Unlike most mountains over the world with O3 maximum in spring or summer, Nanling showed O3 maximum in mid-autumn (October; 62.8 ± 0.7 ppbv, ± 95% confidence intervals) and minimum in summer (July; 46.6 ± 0.7 ppbv). This distinct seasonal cycle of O3 at Nanling was mainly caused by the special impact of Asian monsoon in southern China, which brought clean maritime background air and fresh emissions of the Pearl River Delta (PRD) region in spring/summer, and polluted northern continental air masses in autumn/winter, respectively. Further comparisons found that O3 of Nanling in four seasons were all higher than other similar mountainous background sites, making the annual mean of O3 (55.0 ± 0.2 ppbv) at Nanling the second highest that ever reported in the mountainous sites worldwide. Moreover, the diurnal variation showed the higher impact of regional transport during nighttime from the free troposphere (FT) and presented the potential air exchange between the FT and local atmosphere in the plenary boundary layer on the summit of Nanling. Both the seasonal variation and high O3 level indicated a strong impact of anthropogenic emissions from alternatively PRD/northern China on O3 pollution in this mountainous background region. This study diversifies the seasonal variations among mountains over the world, and also illustrates the complicated impact of anthropogenic emissions on the mountainous atmosphere in southern China.

Salient Ship Detection via Background Prior and Foreground Constraint in Remote Sensing Images

Automatic ship detection in complicated maritime background is a challenging task in the field of optical remote sensing image interpretation and analysis. In this paper, we propose a novel and reliable ship detection framework based on a visual saliency model, which can efficiently detect multiple targets of different scales in complex scenes with sea clutter, clouds, wake and islands interferences. Firstly, we present a reliable background prior extraction method adaptive for the random locations of targets by computing boundary probability and then generate a saliency map based on the background prior. Secondly, we compute the prior probability of salient foreground regions and propose a weighting function to constrain false foreground clutter, gaining the foreground-based prediction map. Thirdly, we integrate the two prediction maps and improve the details of the integrated map by a guided filter function and a wake adjustment function, obtaining the fine selection of candidate regions. Afterwards, a classification is further performed to reduce false alarms and produce the final ship detection results. Qualitative and quantitative evaluations on two public available datasets demonstrate the robustness and efficiency of the proposed method against four advanced baseline methods.

Lean, agile, resilience and green (LARG) paradigm in supply chain operations: a trial in a seaport system

ABSTRACT Seaport inefficiencies have caused hindrances on the seaport operations especially on operational disruption which eventually contributes to high cost expenses, unnecessary waste and environmental pollution, and capital losses. As a result, the business and environmental sustainability cannot be attained and affecting the whole supply chain. Therefore, a Lean, Agile, Resilience and Green (LARG) performance model is proposed as a mechanism to curb these issues and improving the competitiveness of seaports. The compatible LARG criteria in seaport supply chain have been identified and analysed using an extensive literature and expert's reviews. In order to meet the aim of the paper, fifteen (15) experts from various maritime background (i.e. academic and industry experts) have been selected to give the relative important of each LARG paradigms by using an Analytical Hierarchy Process (AHP). The result shows that operational performance has the highest contribution to the seaport supply chain performance followed by economic performance and environmental performance. The outcome of this paper can be utilised as a guideline for seaport practitioners to develop a management tool to boost their performance from the LARG aspect. Furthermore, this LARG management tool can be applied globally as it can be adjusted and adaptable suited the seaport preferences.

A Robust Detection Algorithm for Infrared Maritime Small and Dim Targets.

Infrared maritime target detection is the key technology of maritime target search systems. However, infrared images generally have the defects of low signal-to-noise ratio and low resolution. At the same time, the maritime environment is complicated and changeable. Under the interference of islands, waves and other disturbances, the brightness of small dim targets is easily obscured, which makes them difficult to distinguish. This is difficult for traditional target detection algorithms to deal with. In order to solve these problems, through the analysis of infrared maritime images under a variety of sea conditions including small dim targets, this paper concludes that in infrared maritime images, small targets occupy very few pixels, often do not have any edge contour information, and the gray value and contrast values are very low. The background such as island and strong sea wave occupies a large number of pixels, with obvious texture features, and often has a high gray value. By deeply analyzing the difference between the target and the background, this paper proposes a detection algorithm (SRGM) for infrared small dim targets under different maritime background. Firstly, this algorithm proposes an efficient maritime background filter for the common background in the infrared maritime image. Firstly, the median filter based on the sensitive region selection is used to extract the image background accurately, and then the background is eliminated by image difference with the original image. In addition, this article analyzes the differences in gradient features between strong interference caused by the background and targets, proposes a small dim target extraction operator with two analysis factors that fit the target features perfectly and combines the adaptive threshold segmentation to realize the accurate extraction of the small dim target. The experimental results show that compared with the current popular small dim target detection algorithms, this paper has better performance for target detection in various maritime environments.

An integrated ship segmentation method based on discriminator and extractor

Ship segmentation is an important task in maritime surveillance systems. A great deal of research on image segmentation has been done in the past few years, but there appears to be some problems when directly utilizing them for ship segmentation under complex maritime background. The interference factors decreasing segmentation performance usually are from the peculiarity of complex maritime background, such as the existence of sea fog, large wakes and large waves. To deal with these interference factors, this paper presents an integrated ship segmentation method based on discriminator and extractor (ISDE). Different from traditional segmentation methods, our method consists of two components in light of the structure: Interference Factor Discriminator (IFD) and Ship Extractor (SE). SqueezeNet is employed for the implementation of IFD as the first step to make a judgment on what interference factors are contained in the input image. While DeepLabv3+ and improved DeepLabv3+ are employed for the implementation of SE as the second step to finally extract ships. We collect a ship segmentation dataset and conduct intensive experiments on it. The experimental results demonstrate that our method for ship segmentation outperforms state-of-the-art methods in terms of segmentation accuracy, especially for the images contain sea fog. Besides our method can run in real time as well.

ARKEOLOGI KAWASAN TAPAL BATAS: KONEKSITAS KEPULAUAN MALUKU DAN PAPUA

Maluku and Papua are two areas with the specific characters that geogaphically slocated close to each other. As an archipelagic region Maluku has a dominant maritime background while Papua shows a large and complex continent profile. The specific character as a region has made Maluku became the part of an ecological terminal between Asia and Australia known as Wallacea. Papua, which was the part of Greater Australia Continent in the past, has the similar role as a main corridor to the Pacific. This similarity has made the role of these two region is important in the study of cultural history of Southeast Asia , Australia and the Pacific Islands. This paper is a short review to observe the connecting aspects of Maluku Archipelago and Papua as a border area in the study of regional archaeology.

Automatic detection of sea-sky horizon line and small targets in maritime infrared imagery

It is usually difficult but important to extract distant targets from sea clutters and clouds since the targets are small compared to the pixel field of view. In this paper, an algorithm based on wavelet transformation is proposed for automatic detection of small targets under the maritime background. We recognize that the distant small targets generally appear near the sea-sky horizon line and noises lie along the direction of sea-sky horizon line. So the sea-sky horizon is located firstly by examining the approximate image of a Haar wavelet decomposition of the original image. And the equation of the sea-sky horizon is set up, no matter whether the sea-sky horizon is horizontal or not. Since the sea-sky horizon is located, not only the potential area but also the strip direction of noise is got. Then the modified mutual wavelet energy combination algorithm is applied to extract targets with targets being marked by red windows. Computer simulations are shown to validate the great adaptability of the sea-sky horizon line detection and the accuracy of the small targets detection. The algorithm should be useful to engineers and scientists to design precise guidance or maritime monitoring system.

필리핀 연안수역의 선박교통관제서비스와 해양안전에 관한 설문조사 (Part 1)

이 연구는 필리핀 연안수역의 해양안전과 선박교통관제서비스에 대한 설문조사 결과의 일부를 나타낸 것이다. 이 연구는 응답자의 경력과 육 해상 경험, 친숙해역, 위험요소별 위험지역별 선박운항자의 주관적 위험인식을 조사하였다. 설문은 202명이 응답해 주었고 설문 데이터는 엑셀 프로그램과 통계 프로그램을 이용하여 분석하였다. 전체 응답자의 97 %가 다양한 종류와 크기의 선박에서 승선한 경험이 있었고 88 %는 선박 항해에 직접적으로 종사한 사람이었으며 마닐라 지역(NCR지역)에서 가장 높은 응답률이 있었다. 위험요소별 위험지역별 위험인식 부분에서 위험수준 3단계 '때때로 위험 증가'와 위험수준 4단계 '자주 위험 증가'라는 높은 위험 지표를 보였다. 이 연구에서 가장 높은 위험 요소는 위험수준 5단계 '매우 자주 위험 증가'에 해당되는 "법과 규정의 위반" 으로 나타났다. 그리고 전체 친숙 해역 중 가장 높은 위험 인식을 보인 마닐라 베이 지역(NCR 지역)에서도 역시 위험수준 5단계로 나타났다. 그러므로 각 지역내에서 실행가능한 법과 규정의 광범위한 검토(해상교통체계와 구조물들의 강화, 이해당사자들의 교육(국가의 혼잡 수역, 특히 마닐라 베이 지역))의 실행이 이 연구에 의해 권고된다. 이 연구의 궁극적인 목적은 안전 관련 정보를 수집 분석하여 국내 해상교통안전의 개선과 향상의 지침으로 활용될 기술과 모델을 개발하는 것이다. This paper presents the Part 1 of the Questionnaire Survey on Marine Safety and VTS in the Philippine Coastal Waters. This part deals with respondents profiles; experiences onboard and ashore; familiar areas; and their subjective perception of marine risks- by factors and by areas. The subjects are chosen from different regions nationwide with connection and/or with maritime background. There are 202 responses returned and these are put into a database for analysis made through Excel programs and statistics references. The result of the nationwide responses show that 97 % of respondents have shipboard experiences onboard of different ships' types and sizes; and 88 % are directly involved in the navigation of ships. Risk Perception levels - by factors and by familiar areas - show a higher risk degree in the 3rd level ('Sometimes Increases Risks') and 4th level ('Often Increases Risk') in each respondents' response indices. The study finds that the most risky factor is the "Violation of Rules and Regulations" which has a high risk at 5th level (Very Often Increases Risk), and for the over-all familiar areas, the Manila Bay area (NCR region) garners the most risky perception, also, at the 5th level. It is, therefore, recommended by this paper to conduct a comprehensive review of the rules and regulations viable in each locality; strengthening the maritime traffic systems, structures and educating the stake-holders specifically in Manila Bay area and other busy waterways of the country. The ultimate goal of this paper is to gather information, analyze these data and develop a set of tools and techniques to be utilized as a guide in the improvement and development of maritime traffic safety in the country.

Measurements of molecular hydrogen and carbon monoxide on the Trainou tall tower

We present 2 yr (October 2008 to September 2010) of in situ measurements of molecular hydrogen (H2) and carbon monoxide (CO) sampled at the tall tower of Trainou, France (47.96°N, 02.11°E, 131 masl, sampling height: 50, 100 and 180 m). Radon-222 (222Rn) measurements were added in May 2009. Background seasonal cycles, based on afternoon values, exhibit an amplitude of 45 and 60 ppb for H2 and CO, respectively, for the three different heights (50, 100 and 180 m above ground). The vertical gradient also shows seasonal variations with a maximum (during the night) of 20 and 45 ppb for H2 and CO, respectively.We also observe diurnal cycles for H2 and CO for the three different heights. In the afternoon, the mixing ratios at the three different heights are similar and are comparable with maritime background stations, such as Mace Head (Ireland). The diurnal cycle of 222Rn follows the boundary layer height variations, with maximum values in the morning. Throughout the year but especially in summer and autumn, the H2 mixing ratio shows nighttime depletion, with the lowest values at 06:00 UTC, due to soil uptake and the low boundary layer height. Using a simple box approach and the Radon-Tracer-Method, the H2 deposition velocity is calculated for the catchment area of Trainou.We find a mean value for the H2 deposition velocity of 2.6 ± 0.9 10-2 cm-2 s-1. During wintertime, H2 and CO are sometimes strongly correlated leading to a H2/CO ratio around 0.25. This ratio is lower than the ratio from traffic emissions, thus highlighting the mixing of sources in this area.

DAMA—Infrared Sea Modeling and Analysis Software

The performance of infrared (IR) surveillance systems is proportional to the ability of distinguishing the radiance of target from the background. In determining sea radiance as the background, experimental studies are incomplete and very expensive. The few simulation software packages that are available are limited to certain parameters and do not include all aspects of sea radiance. In this paper, simulation and analysis software, namely, InfrareD SeA Modeling and Analysis (DAMA), is developed to calculate the total radiance and its components seen by the observer. The DAMA software allows the user to define all possible parameters related to atmospheric conditions, sea surface conditions, and date and time of observation. The developed software includes all of the three major sea surface models in the IR band provided in the literature, namely, Cox and Munk, Mermelstein, and Shaw and Churnside models. In this sense, the DAMA software is unique in combining all possible atmospheric and surface parameters to provide components of total radiance. The DAMA software can be operated by a user-friendly graphical user interface to facilitate simulations and to analyze the outputs. For this paper, the software has been run for approximately 10 000 simulations to understand the behavior of maritime background in IR. The software is validated by the SEARAD software and measurement results. By this way, for the first time in the open literature, DAMA allows one to observe the behavior of total radiance and its components with respect to the variation of all possible input parameters.

‘I too would find my ship’: Daphne du Maurier's Passion for the Sea

This article examines the historical contexts for several of Daphne du Maurier's early novels, The Loving Spirit (1931), I'll Never Be Young Again (1932), Jamaica Inn (1932) and Frenchman's Creek (1941). She was strongly drawn to her adopted home in Cornwall and lived among people whose livelihoods depended on the sea. In particular, she first arrived there at a time of economic depression when there was great nostalgia for times past. Her novels reflect her fascination with the sea in all its moods, and the people who worked at sea and ashore. Her creative genius wound fact and fiction into powerful stories and the maritime background was meticulously researched. Her depictions of strong-minded women and coastal communities were unusual for her time. However, in all of this she had limitations that came from her gender, class and experience.

The anthropogenic influence on carbonaceous aerosol in the European background

To constrain the relatively uncertain anthropogenic impact on the organic aerosol load, radiocarbon analyses were performed on aerosol samples, collected year-round, at six non-urban sites including a maritime background and three remote mountain stations, lying on a west-east transect over Western Europe. From a crude three component model supported by TOC and levoglucosan filter data, the fossil fuel, biomass burning and biogenic TOC fraction are estimated, showing at all stations year-round, a relatively constant fossil fuel fraction of around (26 ± 6)%, a dominant biogenic contribution of on average (73 ± 7)% in summer and the continental as well as the maritime background TOC to be only about 50% biogenic. Assuming biomass burning as completely anthropogenic, the carbonaceous aerosol concentration at the mountain sites was found to have increased by a factor of up to (1.4 ± 0.2) in summer and up to (2.5 ± 1.0) in winter. This figure is significantly lower, however, than the respective TOC change since pre-industrial times seen in an Alpine ice core. Reconciling both observations would require an increase, since pre-industrial times, of the background biogenic aerosol load, which is estimated at a factor of 1.3–1.7.

Global aerosol climatology from the MODIS satellite sensors

The recently released Collection 5 Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol products provide a consistent record of the Earth's aerosol system. Comparing with ground‐based AERONET observations of aerosol optical depth (AOD) we find that Collection 5 MODIS aerosol products estimate AOD to within expected accuracy more than 60% of the time over ocean and more than 72% of the time over land. This is similar to previous results for ocean and better than the previous results for land. However, the new collection introduces a 0.015 offset between the Terra and Aqua global mean AOD over ocean, where none existed previously. Aqua conforms to previous values and expectations while Terra is higher than what had been expected. The cause of the offset is unknown, but changes to calibration are a possible explanation. Even though Terra's higher ocean AOD is unexpected and unexplained, we present climatological analyses of data from both sensors. We find that the multiannual global mean AOD at 550 nm over oceans is 0.13 for Aqua and 0.14 for Terra, and over land it is 0.19 in both Aqua and Terra. AOD in situations with 80% cloud fraction are twice the global mean values, although such situations occur only 2% of the time over ocean and less than 1% of the time over land. Aerosol particle size associated with these very cloudy situations does not show a drastic change over ocean, but does over land. Regionally, aerosol amounts vary from polluted areas such as east Asia and India, to the cleanest regions such as Australia and the northern continents. As AOD increases over maritime background conditions, fine mode aerosol dominates over dust over all oceans, except over the tropical Atlantic downwind of the Sahara and during some months over the Arabian Sea.

Western European N2O emissions: A top‐down approach based on atmospheric observations

We present a 3 year record of continuous gas chromatographic nitrous oxide (N2O) observations performed at the urban station Heidelberg (Germany) together with weekly flask data from a remote continental site, Schauinsland (Black Forest, Germany), and two‐weekly integrated data from the maritime background station Izaña (Canary Islands). These data are supplemented by continuous atmospheric radon 222 observations. Mean rates of increase of N2O of 0.70–0.78 ppb yr−1 were observed over the continent and in maritime background air (Izaña). The well‐mixed continental mixing ratio was found to be higher by only 1.1 ppb (Schauinsland) and 2.4 ppb (Heidelberg) than for maritime background air. Specially tailored data selection of the Heidelberg record allowed the changing influence of a regional N2O point source (adipic acid production, BASF AG) to be clearly identified. The radon (222Rn) tracer method was applied to nighttime N2O observations at Heidelberg to estimate mean regional emissions, which changed from (161 ± 32) μg N2O‐N m−2 h−1 in 1996–1997 to (77 ± 10) μg N2O‐N m−2 h−1 in 1998 as a consequence of 90% emission reduction from BASF. An estimate of the continental N2O flux from southwestern Europe based on further selected Heidelberg data (only well‐mixed, late afternoon situations) and observations from the Schauinsland station yielded mean N2O fluxes of (43 ± 5) μg N2O‐N m−2 h−1 and (42 ± 4) μg N2O‐N m−2 h−1. These results compare well with statistical emissions inventories, when taking into account possible systematic errors of the radon tracer method of 30–35%.