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Atmospheric levels of ammonia (NH3) have substantially increased during the last century, posing a hazard to both human health and environmental quality. The atmospheric budget of NH3, however, is still highly uncertain due to an overall lack of observations. Satellite observations of atmospheric NH3 may help us in the current observational and knowledge gaps. Recent observations of the Cross-track Infrared Sounder (CrIS) provide us with daily, global distributions of NH3. In this study, the CrIS NH3 product is assimilated into the LOTOS-EUROS chemistry transport model using two different methods aimed at improving the modeled spatiotemporal NH3 distributions. In the first method NH3 surface concentrations from CrIS are used to fit spatially varying NH3 emission time factors to redistribute model input NH3 emissions over the year. The second method uses the CrIS NH3 profile to adjust the NH3 emissions using a local ensemble transform Kalman filter (LETKF) in a top-down approach. The two methods are tested separately and combined, focusing on a region in western Europe (Germany, Belgium and the Netherlands). In this region, the mean CrIS NH3 total columns were up to a factor 2 higher than the simulated NH3 columns between 2014 and 2018, which, after assimilating the CrIS NH3 columns using the LETKF algorithm, led to an increase in the total NH3 emissions of up to approximately 30 %. Our results illustrate that CrIS NH3 observations can be used successfully to estimate spatially variable NH3 time factors and improve NH3 emission distributions temporally, especially in spring (March to May). Moreover, the use of the CrIS-based NH3 time factors resulted in an improved comparison with the onset and duration of the NH3 spring peak observed at observation sites at hourly resolution in the Netherlands. Assimilation of the CrIS NH3 columns with the LETKF algorithm is mainly advantageous for improving the spatial concentration distribution of the modeled NH3 fields. Compared to in situ observations, a combination of both methods led to the most significant improvements in modeled monthly NH3 surface concentration and NH4+ wet deposition fields, illustrating the usefulness of the CrIS NH3 products to improve the temporal representativity of the model and better constrain the budget in agricultural areas.

Ammonia (NH3) is an essential reactive nitrogen species in the biosphere and through its use in agriculture in the form of fertilizer (important for sustaining humankind). The current emission levels, however, are up to 4 times higher than in the previous century and continue to grow with uncertain consequences to human health and the environment. While NH3 at its current levels is a hazard to environmental and human health, the atmospheric budget is still highly uncertain, which is a product of an overall lack of measurements. The capability to measure NH3 with satellites has opened up new ways to study the atmospheric NH3 budget. In this study, we present the first estimates of NH3 emissions, lifetimes and plume widths from large (>∼ 5 kt yr-1) agricultural and industrial point sources from Cross-Track Infrared Sounder (CrIS) satellite observations across the globe with a consistent methodology. The same methodology is also applied to the Infrared Atmospheric Sounding Interferometer (IASI) (A and B) satellite observations, and we show that the satellites typically provide comparable results that are within the uncertainty of the estimates. The computed NH3 lifetime for large point sources is on average 2:35±1:16 h. For the 249 sources with emission levels detectable by the CrIS satellite, there are currently 55 locations missing (or underestimated by more than an order of magnitude) from the current Hemispheric Transport Atmospheric Pollution version 2 (HTAPv2) emission inventory and only 72 locations with emissions within a factor of 2 compared to the inventories. The CrIS emission estimates give a total of 5622 kt yr-1, for the sources analyzed in this study, which is around a factor of ∼ 2:5 higher than the emissions reported in HTAPv2. Furthermore, the study shows that it is possible to accurately detect short-and long-Term changes in emissions, demonstrating the possibility of using satellite-observed NH3 to constrain emission inventories., SCOPUS: ar.j, info:eu-repo/semantics/published

International audience; Transport of biomass burning emissions into the Arctic can cause episodic enhancements of multiple trace gas species. We present a multi-year time series of the total columns of carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C2H6) measured using Fourier Transform Infrared (FTIR) solar absorption spectroscopy at six high-latitude sites: Eureka, Nunavut; Ny Alesund, Norway; Thule, Greenland; Kiruna, Sweden; Poker Flat, Alaska; and St. Petersburg, Russia, and at three mid-latitude sites; Zugspitze, Germany; Jungfraujoch, Switzerland; and Toronto, Ontario. For each site, the inter-annual trends and seasonal variabilities of the CO total column time series are determined and enhancements above ambient levels are used to identify possible wildfire pollution events. Correlations of HCN and C2H6 with CO, back-trajectories from HYSPLIT and FLEXPART, and fire locations from the Moderate Resolution Spectroradiometer (MODIS) confirm the detections and identify the source regions. The GEOS-Chem chemical transport model is run in tagged mode to determine the relative contributions to the observed enhancements from continental-scale biomass burning source regions.Exceptional emissions of CO, HCN, C2H6, and ammonia (NH3) from the 2017 North American wildfires were measured at Eureka and Thule, indicating that wildfires may be a major source of NH3 in the summertime high Arctic. The enhancement ratios of the long- lived species HCN and C2H6 are found to be comparable between sites, but for NH3, the enhancement ratios are strongly dependent on the transport patterns of the smoke plumes. Satellite measurements of NH3 from the Infrared Atmospheric Sounding Instrument (IASI) and Cross-track Infrared Sounder (CrIS) are used to examine the spatial and temporal variabilities of NH3. Comparisons to a high-resolution (0.25° x 0.3125°) nested run of GEOS-Chem using emissions from the Global Fire Assimilation System (GFAS) are performed to evaluate the emission inventories and assess the long-range transport of NH3 to the high Arctic.

Atmospheric levels of reactive nitrogen have increased substantially during the last century resulting in increased nitrogen deposition to ecosystems, causing harmful effects such as soil acidification, reduction in plant biodiversity and eutrophication in lakes and the ocean. Recent developments in the use of atmospheric remote sensing enabled us to resolve concentration fields of NH3 with larger spatial coverage. These observations may be used to improve the quantification of NH3 deposition. In this paper, we use a relatively simple, data-driven method to derive dry deposition fluxes and surface concentrations of NH3 for Europe and for the Netherlands. The aim of this paper is to determine the applicability and the limitations of this method for NH3. Space-born observations of the Infrared Atmospheric Sounding Interferometer (IASI) and the LOTOS-EUROS atmospheric transport model are used. The original modelled dry NH3 deposition flux from LOTOS-EUROS and the flux inferred from IASI are compared to indicate areas with large discrepancies between the two. In these areas, potential model or emission improvements are needed. The largest differences in derived dry deposition fluxes occur in large parts of central Europe, where the satellite-observed NH3 concentrations are higher than the modelled ones, and in Switzerland, northern Italy (Po Valley) and southern Turkey, where the modelled NH3 concentrations are higher than the satellite-observed ones. A sensitivity analysis of eight model input parameters important for NH3 dry deposition modelling showed that the IASI-derived dry NH3 deposition fluxes may vary from ĝ1/4 20 % up to ĝ1/4 50 % throughout Europe. Variations in the NH3 dry deposition velocity led to the largest deviations in the IASI-derived dry NH3 deposition flux and should be focused on in the future. A comparison of NH3 surface concentrations with in situ measurements of several established networks - the European Monitoring and Evaluation Programme (EMEP), Meetnet Ammoniak in Natuurgebieden (MAN) and Landelijk Meetnet Luchtkwaliteit (LML) - showed no significant or consistent improvement in the IASI-derived NH3 surface concentrations compared to the originally modelled NH3 surface concentrations from LOTOS-EUROS. It is concluded that the IASI-derived NH3 deposition fluxes do not show strong improvements compared to modelled NH3 deposition fluxes and there is a future need for better, more robust, methods to derive NH3 dry deposition fluxes. © Author(s) 2018.

Limited availability of ammonia (NH3) observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007, the Infrared Atmospheric Sounding Interferometer (IASI) satellite has been observing NH3 from space at a high spatio-temporal resolution. This valuable data set, already used by models, still needs validation. We present here a first attempt to validate IASI-NH3 measurements using existing independent ground-based and airborne data sets. The yearly distributions reveal similar patterns between ground-based and space-borne observations and highlight the scarcity of local NH3 measurements as well as their spatial heterogeneity and lack of representativity. By comparison with monthly resolved data sets in Europe, China and Africa, we show that IASI-NH3 observations are in fair agreement, but they are characterized by a smaller variation in concentrations. The use of hourly and airborne data sets to compare with IASI individual observations allows investigations of the impact of averaging as well as the representativity of independent observations for the satellite footprint. The importance of considering the latter and the added value of densely located airborne measurements at various altitudes to validate IASI-NH3 columns are discussed. Perspectives and guidelines for future validation work on NH3 satellite observations are presented.

Presented here is the validation of the CrIS (Cross-track Infrared Sounder) fast physical NH3 retrieval (CFPR) column and profile measurements using ground-based Fourier transform infrared (FTIR) observations. We use the total columns and profiles from seven FTIR sites in the Network for the Detection of Atmospheric Composition Change (NDACC) to validate the satellite data products. The overall FTIR and CrIS total columns have a positive correlation of r = 0.77 (N = 218) with very little bias (a slope of 1.02). Binning the comparisons by total column amounts, for concentrations larger than 1.0 × 1016 molecules cm−2, i.e. ranging from moderate to polluted conditions, the relative difference is on average ∼ 0–5 % with a standard deviation of 25–50 %, which is comparable to the estimated retrieval uncertainties in both CrIS and the FTIR. For the smallest total column range (16 molecules cm−2) where there are a large number of observations at or near the CrIS noise level (detection limit) the absolute differences between CrIS and the FTIR total columns show a slight positive column bias. The CrIS and FTIR profile comparison differences are mostly within the range of the single-level retrieved profile values from estimated retrieval uncertainties, showing average differences in the range of ∼ 20 to 40 %. The CrIS retrievals typically show good vertical sensitivity down into the boundary layer which typically peaks at ∼ 850 hPa (∼ 1.5 km). At this level the median absolute difference is 0.87 (std = ±0.08) ppb, corresponding to a median relative difference of 39 % (std = ±2 %). Most of the absolute and relative profile comparison differences are in the range of the estimated retrieval uncertainties. At the surface, where CrIS typically has lower sensitivity, it tends to overestimate in low-concentration conditions and underestimate in higher atmospheric concentration conditions.

Presented here is the validation of the CrIS (Cross-track Infrared Sounder) fast physical NH3 retrieval (CFPR) column and profile measurements using ground-based Fourier transform infrared (FTIR) observations. We use the total columns and profiles from seven FTIR sites in the Network for the Detection of Atmospheric Composition Change (NDACC) to validate the satellite data products. The overall FTIR and CrIS total columns have a positive correlation of Combining double low line ĝ€0.77 (N =218) with very little bias (a slope of 1.02). Binning the comparisons by total column amounts, for concentrations larger than 1.0 × 1016 molecules cm-2, i.e. ranging from moderate to polluted conditions, the relative difference is on average ∼0 5% with a standard deviation of 25-50%, which is comparable to the estimated retrieval uncertainties in both CrIS and the FTIR. For the smallest total column range (< 1.0 × 1016molecules cm-2) where there are a large number of observations at or near the CrIS noise level (detection limit) the absolute differences between CrIS and the FTIR total columns show a slight positive column bias. The CrIS and FTIR profile comparison differences are mostly within the range of the single-level retrieved profile values from estimated retrieval uncertainties, showing average differences in the range of 20 to 40%. The CrIS retrievals typically show good vertical sensitivity down into the boundary layer which typically peaks at 850hPa (g 1.5km). At this level the median absolute difference is 0.87(std =±0.08)ppb, corresponding to a median relative difference of 39%(std =±2%). Most of the absolute and relative profile comparison differences are in the range of the estimated retrieval uncertainties. At the surface, where CrIS typically has lower sensitivity, it tends to overestimate in low-concentration conditions and underestimate in higher atmospheric concentration conditions.

Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs Combining double low line 547) give a mean relative difference of ĝ'32.4ĝ€±ĝ€(56.3)ĝ€%, a correlation r of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (-50 to +100%).

An overview of the achievements and the current state of knowledge on reactive nitrogen in Europe, focusing on deposition, critical load exceedances, and modeled and measured trends.

The delta region between Rotterdam and Antwerp is a prime example of an area where spatial develoments face increasing complexity. This complexity demands a new approach to spatial planning and design. This book is a result of a research project aimed to develop such a new planning practice. The research conceived of the Southwest Delta of the Netherlands as laboratory for the new approach, which has nonetheless also proven relevant to other regions dealing with similar level of complexity.

International audience; We exploit six years of measurements from the IASI/MetOp-A instrument to identify seasonal patterns and inter-annual variability of atmospheric NH3. This is achieved by analyzing the time evolution of the monthly-mean NH3 columns in 12 subcontinental areas around the world, simultaneously considering measurements from IASI morning and evening overpasses. For most regions, IASI has a sufficient sensitivity throughout the years to capture the seasonal patterns of NH3 columns, and we show that each region is characterized by a well-marked and distinctive cycle, with maxima mainly related to underlying emission processes. The largest column abundances and seasonal amplitudes throughout the years are found in Southwestern Asia,with maxima twice as large as what is observed in Southeastern China. The relation between emission sources and retrieved NH3 columns is emphasized at smaller regional scale by inferring a climatology of the month of maximum columns.

Monitoring ammonia (NH3) concentrations on a global to regional scale is a challenge. Due to the limited availability of reliable ground-based measurements, the determination of NH3 distributions generally relies on model calculations. Novel remotely sensed NH3burdens provide valuable insights to complement traditional assessments for clear-sky conditions. This paper presents a first quantitative comparison between Atmospheric Sounding Interferometer (IASI) satellite observations and LOTOS-EUROS model results over Europe and Western Russia. A methodology to account for the variable retrieval sensitivity of the measurements is described. Four years of data (2008-2011) highlight three main agricultural hot spot areas in Europe: the Po Valley, the continental part of Northwestern Europe, and the Ebro Valley. The spatial comparison reveals a good overall agreement of the NH3 distributions not only in these source regions but also over remote areas and over sea when transport is observed. On average, the measured columns exceed the modeled ones, except for a few cases. Large discrepancies over several industrial areas in Eastern Europe and Russia point to underestimated emissions in the underlying inventories. The temporal analysis over the three hot spot areas reveals that the seasonality is well captured by the model when the lower sensitivity of the satellite measurements in the colder months is taken into account. Comparison of the daily time series indicates possible misrepresentations of the timing and magnitude of the emissions. Finally, specific attention to biomass burning events shows that modeled plumes are less spread out than the observed ones. This is confirmed for the 2010 Russian fires with a comparison using in situ observations. ©2014. American Geophysical Union. All Rights Reserved.

Dit boek is een pleidooi voor een nieuwe aanpak van ruimtelijke planvorming in complexe stedelijke deltagebieden. Het onderzoek werd uitgevoerd in de periode 2011-2013 door een consortium van drie universiteiten (Technische Universiteit Delft, Wageningen Universiteit en Erasmus Universiteit Rotterdam), vier kennisinstituten (Deltares, TNO, PBL en Geodan) en vier adviesbureaus (MUST Stedebouw, H+N+S Landschaparchitecten, RoyalHaskoningDHV en HKV lijn in water). Het onderzoek richtte zich vooral op het gebied van de Zuidwestelijke delta tussen Rotterdam en Antwerpen.

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Het Planbureau voor de Leefomgeving (PBL) brengt elke vier jaar een Natuurverkenning uit. Dit is één van de wettelijke taken van het planbureau. Een toekomstverkenning is bedoeld om toekomstige maatschappelijke ontwikkelingen en nieuwe beleidsopties te verkennen en daarmee het blikveld te verruimen. Deze Natuurverkenning zoekt aansluiting bij de huidige politieke en maatschappelijke discussie over de richting van het natuur- en landschapsbeleid. Het is de vierde Natuurverkenning die het PBL en zijn voorlopers hebben uitgebracht. De eerste en de tweede (RIVM 1997; 2002) zijn als zelfstandige studies verschenen en de derde als onderdeel van Nederland later (MNP 2006)

De omgevingsscenario’s Hoog en Laag zijn ontwikkeld om te verkennen of de beleidsopgaven waarop de kijkrichtingen van de Natuurverkenning 2010-2040 een antwoord geven in de toekomst ook nog relevant zullen zijn en hoe groot zij dan kunnen zijn. Daarnaast geven zij inzicht in de mogelijkheden en beperkingen waarmee het beleid te maken kan krijgen en daarmee in de realiseerbaarheid van het beleid. De basis voor scenario Hoog wordt gevormd door een sterke internationale oriëntatie en veel marktwerking. Binnen de Europese Unie is er sprake van verdergaande economische en financiële integratie; het Europese natuur- en landbouwbeleid wordt juist minder ambitieus. Er is sprake van een stevige economische groei en een toename van de bevolkingsomvang. Het resultaat is dat de ruimte- en milieudruk in ons land sterk toeneemt. De basis voor scenario Laag betreft een focus op de eigen regio en op de collectieve sector. In Laag komt een verdere mondiale handelsliberalisatie niet van de grond en valt de wereld in een aantal handelsblokken uiteen. Het Europese beleid wordt sterker op duurzaamheid gericht. Bedrijven en burgers zijn vooral op de eigen regio en eveneens op duurzaamheid gericht. De economische groei is laag en de bevolking krimpt uiteindelijk. Als gevolg van deze ontwikkelingen neemt ruimtedruk nauwelijks toe en neemt de milieudruk af. Als de opgaven in de context van de omgevingsscenario’s worden geplaatst, blijven ze robuust. Het belang en de absolute omvang van de opgave kunnen wel verschuiven, afhankelijk van het omgevingsscenario. Tevens zitten er in de omgevingsscenario’s elementen die tegengesteld kunnen uitwerken op de omvang en het belang van een opgave. De realiseerbaarheid van de kijkrichtingen kan worden beïnvloed door de individuele en onderling samenhangende of elkaar juist elkaar tegenwerkende ontwikkelingen van de diverse drijvende krachten. In Hoog kan vooral de economische situatie een gunstige invloed hebben op de realiseerbaarheid van de kijkrichtingen. De ruimtedruk kan realiseerbaarheid van Inpasbare natuur vergroten, maar kan negatief uitwerken op de realiseerbaarheid van de andere drie kijkrichtingen. In dit scenario is er niet zoveel maatschappelijke en bestuurlijke aandacht voor collectieve goederen als natuur en milieu, wat de realisatie van Vitaal en Functioneel niet ten goede komt. In Laag is er juist wel maatschappelijke en politieke aandacht voor collectieve goederen als natuur en milieu en bieden ook het Gemeenschappelijk Landbouwbeleid en de ruimtelijke invulling van klimaatadaptatie in veel gevallen kansen voor de realisatie van de kijkrichting Vitale, Functionele of Beleefbare natuur. Daarbij is het niet altijd vanzelfsprekend dat wat goed is voor Functioneel ook goed is voor bijvoorbeeld Beleefbaar. Denk daarbij aan klimaatadaptatiemaatregelen. Deze hoeven niet altijd te leiden tot beleefbare natuur. De economische situatie waarin scenario Laag zich bevindt, kan voor alle drie de scenario’s een negatieve uitwerking hebben op de realisatiekansen. De bestuurlijke en maatschappelijke context maakt de realisatie van Inpasbare natuur moeilijk. Uit de kwalitatieve toetsing blijkt dat beide mogelijke toekomstige omgevingen drijvende krachten bevatten die een positieve, kunnen hebben op de realisatiekansen van iedere kijkrichting, maar ook drijvende krachten die een negatieve uitwerking kunnen hebben. Belangrijk is om deze drijvende krachten te herkennen en er op een adequate manier op in te spelen.

Planbureau voor de Leefomgeving (PBL), Centraal Planbureau (CPB), KNMI en Wageningen UR, LEI publiceren onder leiding van Deltares de ‘Deltascenario’s voor 2050 en 2100 – nadere uitwerking 2012-2013’. Deze scenario’s bouwen voort op de in 2011 gepubliceerde Deltascenario’s. Ze zijn gebaseerd op meer óf minder economische groei in combinatie met matige óf grote klimaatverandering. De vier scenario’s hebben de namen: RUST (resultaat van matige klimaatverandering en lage groei van economie en bevolking); DRUK (matige klimaatverandering, sterke groei); WARM (snelle klimaatverandering, lage groei); STOOM (snelle klimaatverandering, sterke groei). Aan de hand van elk van de uitgewerkte scenario’s toont het consortium voor welke uitdagingen Nederland in de toekomst kan komen te staan als het gaat om zoetwatervoorziening, de ruimtelijke inrichting van stad en land en bescherming tegen overstromingen.

In dit cahier wordt in beknopte vorm verslag gedaan van het onderzoeksproject Integrated Planning and Design in the Delta (IPDD), dat in de periode 2011-2013 is uitgevoerd als onderdeel van het NWO programma Urban Regions in the Delta (URD). Zoals alle URD projecten, is het doel van het IPDD project om kennis te ontwikkelen voor een duurzaam ruimtelijk beleid en voor integrale gebiedsontwikkeling in stedelijke netwerken. De aanleiding hiervan is de transitie waarin ruimtelijk beleid en gebiedsontwikkeling zich bevinden. De sterke cultuur en het institutionele raamwerk van het naoorlogse ruimtelijk beleid, door Faludi en van der Valk als de ‘Dutch planning doctine’ beschreven, en waarmee Nederland internationaal een status als gidsland verwierf, is uitgewerkt. Vooralsnog is niet een vanzelfsprekend alternatief ontstaan.