Comparação de métodos para ajuste de modelos de semivariograma da precipitação pluvial anual.

Comumente dados de precipitação pluvial apresentam variação e a obtenção da estimativa de sua distribuição espacial é primordial no planejamento agrícola e ambiental. O objetivo neste trabalho foi comparar o método de estimação dos mínimos quadrados ponderados para ajuste de modelos ao semivariograma com o método de tentativa e erro, através da técnica de auto-validação "jack-knifing", para dados de precipitação pluvial média anual do Estado de São Paulo. Observações de precipitação correspondentes ao período de 1957 a 1997 foram usadas para trezentos e setenta e nove (379) estações pluviométricas abrangendo todo o Estado de São Paulo, representando uma área de aproximadamente 248.808,8 km². A periodicidade exibida pelos semivariogramas foi ajustada pelo modelo "hole effect", em que os parâmetros foram estimados com maior precisão pelo método de mínimos quadrados ponderados quando comparado com o método de tentativa e erro. O método de auto-validação "jack-knifing" mostrou-se adequado para a definição de métodos e modelos a serem usados para semivariâncias, cujo procedimento permitiu definir dezesseis vizinhos como o número ideal para a estimativa por krigagem de valores de precipitação pluvial para locais não amostrados no Estado de São Paulo.

Variabilidade patogênica e molecular entre isolados de Colletotrichum lindemuthianum oriundos de diferentes regiões produtoras de feijão no Brasil.

Este trabalho teve por objetivo estudar a distribuição populacional de isolados do fungo C. lindemuthianum provenientes de diferentes regiões do Brasil, além de identificar se a variação genética existente é intra ou inter-racial, utilizando cultivares diferenciadoras e marcadores RAPD.

Variabilidade da fertilidade do solo em um sistema de integração lavoura-pecuária-floresta.

2016

GEOGRAFIA DA SAÚDE: PRESSUPOSTOS TEÓRICOS E O ESTUDO DA RELAÇÃO DA PRECIPITAÇÃO COM OS CASOS DE DENGUE NO MUNICÍPIO DE EUSÉBIO-CE-BRASIL

Esta pesquisa insere-se dentro do campo de estudo da ciência geográfica denominada Geografia da Saúde, ramo este que tem contribuído para as discussões no âmbito da Geografia. Deste modo, este estudo busca no arcabouço teórico da Geografia da Saúde sua fundamentação para relacionar a precipitação com os casos de dengue no município de Eusébio, que se localiza na Região Metropolitana de Fortaleza-CE/Brasil. A referida cidade é considerada de pequeno porte, com uma população 46.047 habitantes (IBGE, 2010). Contudo, têm crescido em ritmo acelerado e, desta forma, é necessário cuidado com os problemas socioambientais, uma vez que são nas cidades que estes riscos são mais observados. É nesta perspectiva que relaciona-se os casos de dengue no município do Eusébio com a precipitação nos últimos anos, haja vista que o município é um modelo para o Estado do Ceará de controle e combate a dengue. Esta cidade está inserida dentro de uma política cearense de combate a proliferação do Aedes Aegypti - Programa Nacional de Controle da Dengue (PNCD). Neste contexto, verifica-se a relação dos fatores climáticos - precipitação com o acréscimo dos casos de dengue no município. Entretanto, não dissociou-se os aspectos físicos que propiciam a proliferação do mosquito, da questão social, assim, averigua-se também a intervenção das políticas públicas para o controle dos casos de dengue no município.

A EXPANSÃO DO ESPAÇO URBANO DA CIDADE DE AQUIDAUANA-MS/BRASIL E AS CAUSAS DA PROLIFERAÇÃO DA DENGUE

O crescimento e o adensamento populacional urbano no Brasil e particularmente na cidade de Aquidauana-MS tem se convertido em aspectos agravantes envolvendo a saúde. Referindo-se a área de estudo, a expansão urbana tem ocorrido no sentido norte, caracterizando como uma área periférica, com saneamento básico e ambiental deficitário, existência de hábitos vida rural no urbano, possibilitando o surgimento e ressurgimento de alguns males da saúde humana como, por exemplo, a dengue. O presente estudo contempla análise entre os casos notificados e confirmados da Dengue no espaço urbano de Aquidauana-MS relacionado com os elementos climáticos, especificamente: Temperatura e Precipitação. Partindo da hipótese de averiguar se o processo de urbanização da cidade de Aquidauana-MS pode ser responsabilizado pela ocorrência de episódios relativos a dengue e ao clima, este trabalho utiliza-se do método hipotético-dedutivo, trazendo uma reflexão dialética dos processos e formas espaciais a partir da ação dos agentes sociais modeladores do espaço urbano. Os resultados apontam correlações entre a produção do espaço urbano, os elementos climáticos e a saúde, além do desenvolvimento de determinados vetores.

Soma térmica em dois anos consecutivos e de meteorologia distinta para cafeeiros plantados em Varginha - MG.

O cálculo da soma térmica ou dos graus dia acumulados (GDA) é um a maneira de correlacionar as variações da temperatura média diária com o desenvolvimento das plantas, que se dá pela sucessão de estágios fisiológicos reconhecíveis. O cálculo da soma térmica vem sendo aplicado a cafeeiros desde a década de 80, e há dois anos tem sido aplicado a cafeeiros arabica Arara, Sabiá e Siriema, plantados na Fazenda Experimental da Fundação Procafé, em Varginha com a expectativa de que contribua para caracterizar detalhadamente sua interação com as variações do clima. O objetivo deste trabalho foi comparar resultados obtidos durante o ciclo reprodutivo dos anos 2014/15 e 2015/16, para as fases de antese até formação de chumbinhos e dos chumbinhos até o grão verde.

Variabilidade de dados de produção de grãos e de palhada em talhões de sistemas intensificados envolvendo milho, soja e braquiária.

2016

Variabilidade em populações naturais de mangabeira do litoral de Pernambuco.

2006

Giovani. Variabilidade de parâmetros biológicos e genéticos de Cotesia flavipes (Cameron, 1891) (Hymenoptera: Braconidae) no Brasil.

2016

Lentosääennusteiden merkitys

Tässä työssä selvitetään lentosääennusteiden käyttöä lennon suunnittelun ja toteutuksen perusteena. Tuodaan esille määräyksiä ja lentosäätietojen käyttöä kaikissa lennon vaiheissa. Perehdytään ennustettujen olosuhteiden ja ennusteiden laadun merkitykseen lentojen toteutuksessa. Selvitetään lentosääennusteisiin liittyviä lentoliikenteen kustannuksia. Työn aineistona käytettiin joulukuu 2006 - heinäkuu 2007 välisenä aikana eri pituisina jaksoina kerättyä 185 liikennelennon lennonsuunnittelumateriaalia ja 126 satunnaisella otoksella otettuja Suomen GAFOR -ennusteita. Liikennelennot toteutettiin Suomen ja Euroopan alueella. Työssä todennettiin METAR –lentopaikkasanoman avulla TAF -lentopaikka-, TREND -laskeutumis-, GAFOR -yleisilmailuennusteita. Yleisestä sääpalvelusta saatua materiaalia käsiteltiin EXCEL –taulukkolaskentaohjelmalla Lentosääennusteita käsiteltiin usean eri käyttäjäryhmän kannalta. Reittilentomittauksilla tutkittiin SIGMET –varoituspalvelun, SWC –merkitsevän sään ja yläilmakehän tuulen sekä lämpötilan ennusteita. TAF –pilvikorkeusennusteiden keskimääräinen hyvyysluku oli lähes sama pilvikorkeudesta riippumatta. Suhteellisen hyvissä olosuhteissa toimivat käyttäjät saivat ennusteista paljon hyötyä. Vaakanäkyvyysennusteiden keskimääräinen hyvyysluku oli suurempi hyvissä kuin huonoissa olosuhteissa. Huonojen olosuhteiden ennusteet olivat lentotoiminnalle enemmän harmillisia kuin hyödyllisiä. Ennustustyö olisi tarvinnut apuvälinettä. Tutkittiin TREND –ennusteiden ominaista osuvuutta. NOSIG –ennuste oli suhteellisen usein julkaistu vaikka sitä seurasi olosuhteen muutos. BECMG -ennuste toteutui pääsääntöisesti ennusteajan alkupuolella. Ajoittaisten olosuhdemuutosten aikana TEMPO -ennusteita julkaistiin hyvin, mutta ennusteen osuvuus vaihteli. Tässä muodossa jaettu ennustetieto ei palvele kovin hyvin päätöstilannetta, jossa on arvioitava polttoaineen riittävyys lennon loppuosalle. GAFOR -pintatuuliennusteet olivat onnistuneita kuten TAF -ennusteissa. Vaakanäkyvyys- ja pilvikorkeusolosuhteissa vertailupisteissä oli 10% havainnoista ennustettua huonompaa olosuhdetta, jos käytettiin vain GAFOR –ennusteen perusosaa lennonsuunnittelussa ja 6% havainnoista, jos käytettiin koko ennustetta. Ilma-aluksen päällikön on valvottava näkölento-olosuhteiden kehitystä lennon aikana ja varmistettava aina näkölento-olosuhteinen lentoreitti laskupaikalle. Lentosääennusteet ovat osa lentotoimintaa mahdollistavaa järjestelmää. Ennusteet hallitsevat vaihtelevasti olosuhteita ja luonnollisesti aiheuttavat ongelmallisia tilanteita. Käyttäjiä sitovat määräykset on luotu, jotta toiminta olisi turvallista. Laadukkaita ennusteita tarvitaan isoilla liikennepaikoilla lentoliikenteen kapasiteetin hallintaan. Pienillä lentopaikoilla laitevarustus ei vielä takaa lentotoimintaa kaikissa olosuhteissa. Näkölentotoimintaa harjoitetaan jatkuvasti sekä hyvissä että kohtalaisen huonoissa olosuhteissa.

Satelliitti-instrumentti IASI ja sen sovellukset sääpalvelulle

IASI on vuodesta 2007 käytössä ollut satelliitti-instrumentti Metop-polaarisatelliitissa. IASI-mittauksista johdettuja lopputuotteita ovat mm. lämpötilan ja kosteuden pystyprofiilit, pilven ylärajan lämpötila ja paine sekä eri hivenkaasujen pitoisuudet. Tämä työ on alkua IASI:n käyttöönotolle Ilmatieteen laitoksella. Työssä selvitetään IASI:n lämpötilaprofiileiden ja pilven ylärajan paineen soveltuvuutta sääpalvelulle vertailemalla niitä jo käytössä oleviin sääpalvelun työkaluihin. IASI-mittauksista johdettuja lämpötilaprofiileita verrataan Ilmatieteen laitoksen operatiivisiin pintaluotauksiin. Lisäksi tarkastellaan IASI:n lämpötilaprofiileiden vaikutusta paikallisen analyysi- ja ennustustyökalu LAPS:in lämpötila-analyysiin. IASI:n pilven ylärajan lämpötiloja verrataan AVHRR-radiometrista johdettuihin pilven ylärajan lämpötiloihin. IASI:sta ja AVHRR:stä johdetut keskimääräiset lämpötilat olivat lähes samat alapilville. Yläpilville ja osittain läpinäkyville cirrus-pilville lämpötilaero oli noin 5 Celsius-astetta. IASI:n lämpötilaluotaukset osoittautuivat käyttökelpoisiksi etenkin keski- ja ylätroposfäärissä (350 - 600 hPa), jossa IASI:n antama lämpötila erosi pintaluotauksen lämpötilasta vain noin +-1 Celsius-astetta. IASI:n lämpötilaluotausten suurin ongelma on mittausten katkeaminen pilven ylärajaan. IASI-luotauksilla oli suuri vaikutus LAPS-lämpötila-analyysiin mallin koko alueella, mutta vertailuaineiston puutteessa ei voida varmasti sanoa onko vaikutus positiivinen vai negatiivinen. Tulokset ovat lupaavia. IASI:n lämpötilaluotaukset ja pilven ylärajan lämpötila vaikuttavat käyttökelpoisilta sääpalvelun tarpeisiin.

Towards the Use of Radar Winds in Numerical Weather Prediction

Numerical weather prediction (NWP) models provide the basis for weather forecasting by simulating the evolution of the atmospheric state. A good forecast requires that the initial state of the atmosphere is known accurately, and that the NWP model is a realistic representation of the atmosphere. Data assimilation methods are used to produce initial conditions for NWP models. The NWP model background field, typically a short-range forecast, is updated with observations in a statistically optimal way. The objective in this thesis has been to develope methods in order to allow data assimilation of Doppler radar radial wind observations. The work has been carried out in the High Resolution Limited Area Model (HIRLAM) 3-dimensional variational data assimilation framework. Observation modelling is a key element in exploiting indirect observations of the model variables. In the radar radial wind observation modelling, the vertical model wind profile is interpolated to the observation location, and the projection of the model wind vector on the radar pulse path is calculated. The vertical broadening of the radar pulse volume, and the bending of the radar pulse path due to atmospheric conditions are taken into account. Radar radial wind observations are modelled within observation errors which consist of instrumental, modelling, and representativeness errors. Systematic and random modelling errors can be minimized by accurate observation modelling. The impact of the random part of the instrumental and representativeness errors can be decreased by calculating spatial averages from the raw observations. Model experiments indicate that the spatial averaging clearly improves the fit of the radial wind observations to the model in terms of observation minus model background (OmB) standard deviation. Monitoring the quality of the observations is an important aspect, especially when a new observation type is introduced into a data assimilation system. Calculating the bias for radial wind observations in a conventional way can result in zero even in case there are systematic differences in the wind speed and/or direction. A bias estimation method designed for this observation type is introduced in the thesis. Doppler radar radial wind observation modelling, together with the bias estimation method, enables the exploitation of the radial wind observations also for NWP model validation. The one-month model experiments performed with the HIRLAM model versions differing only in a surface stress parameterization detail indicate that the use of radar wind observations in NWP model validation is very beneficial.

Exploiting ground-based measurements of the Global Positioning System for numerical weather prediction

Data assimilation provides an initial atmospheric state, called the analysis, for Numerical Weather Prediction (NWP). This analysis consists of pressure, temperature, wind, and humidity on a three-dimensional NWP model grid. Data assimilation blends meteorological observations with the NWP model in a statistically optimal way. The objective of this thesis is to describe methodological development carried out in order to allow data assimilation of ground-based measurements of the Global Positioning System (GPS) into the High Resolution Limited Area Model (HIRLAM) NWP system. Geodetic processing produces observations of tropospheric delay. These observations can be processed either for vertical columns at each GPS receiver station, or for the individual propagation paths of the microwave signals. These alternative processing methods result in Zenith Total Delay (ZTD) and Slant Delay (SD) observations, respectively. ZTD and SD observations are of use in the analysis of atmospheric humidity. A method is introduced for estimation of the horizontal error covariance of ZTD observations. The method makes use of observation minus model background (OmB) sequences of ZTD and conventional observations. It is demonstrated that the ZTD observation error covariance is relatively large in station separations shorter than 200 km, but non-zero covariances also appear at considerably larger station separations. The relatively low density of radiosonde observing stations limits the ability of the proposed estimation method to resolve the shortest length-scales of error covariance. SD observations are shown to contain a statistically significant signal on the asymmetry of the atmospheric humidity field. However, the asymmetric component of SD is found to be nearly always smaller than the standard deviation of the SD observation error. SD observation modelling is described in detail, and other issues relating to SD data assimilation are also discussed. These include the determination of error statistics, the tuning of observation quality control and allowing the taking into account of local observation error correlation. The experiments made show that the data assimilation system is able to retrieve the asymmetric information content of hypothetical SD observations at a single receiver station. Moreover, the impact of real SD observations on humidity analysis is comparable to that of other observing systems.

On the behaviour of some physical parameterization methods in high-resolution numerical weather prediction models

Modern-day weather forecasting is highly dependent on Numerical Weather Prediction (NWP) models as the main data source. The evolving state of the atmosphere with time can be numerically predicted by solving a set of hydrodynamic equations, if the initial state is known. However, such a modelling approach always contains approximations that by and large depend on the purpose of use and resolution of the models. Present-day NWP systems operate with horizontal model resolutions in the range from about 40 km to 10 km. Recently, the aim has been to reach operationally to scales of 1 4 km. This requires less approximations in the model equations, more complex treatment of physical processes and, furthermore, more computing power. This thesis concentrates on the physical parameterization methods used in high-resolution NWP models. The main emphasis is on the validation of the grid-size-dependent convection parameterization in the High Resolution Limited Area Model (HIRLAM) and on a comprehensive intercomparison of radiative-flux parameterizations. In addition, the problems related to wind prediction near the coastline are addressed with high-resolution meso-scale models. The grid-size-dependent convection parameterization is clearly beneficial for NWP models operating with a dense grid. Results show that the current convection scheme in HIRLAM is still applicable down to a 5.6 km grid size. However, with further improved model resolution, the tendency of the model to overestimate strong precipitation intensities increases in all the experiment runs. For the clear-sky longwave radiation parameterization, schemes used in NWP-models provide much better results in comparison with simple empirical schemes. On the other hand, for the shortwave part of the spectrum, the empirical schemes are more competitive for producing fairly accurate surface fluxes. Overall, even the complex radiation parameterization schemes used in NWP-models seem to be slightly too transparent for both long- and shortwave radiation in clear-sky conditions. For cloudy conditions, simple cloud correction functions are tested. In case of longwave radiation, the empirical cloud correction methods provide rather accurate results, whereas for shortwave radiation the benefit is only marginal. Idealised high-resolution two-dimensional meso-scale model experiments suggest that the reason for the observed formation of the afternoon low level jet (LLJ) over the Gulf of Finland is an inertial oscillation mechanism, when the large-scale flow is from the south-east or west directions. The LLJ is further enhanced by the sea-breeze circulation. A three-dimensional HIRLAM experiment, with a 7.7 km grid size, is able to generate a similar LLJ flow structure as suggested by the 2D-experiments and observations. It is also pointed out that improved model resolution does not necessary lead to better wind forecasts in the statistical sense. In nested systems, the quality of the large-scale host model is really important, especially if the inner meso-scale model domain is small.

Turbulent vertical fluxes and air quality measured in urban air in Helsinki

There is a growing need to understand the exchange processes of momentum, heat and mass between an urban surface and the atmosphere as they affect our quality of life. Understanding the source/sink strengths as well as the mixing mechanisms of air pollutants is particularly important due to their effects on human health and climate. This work aims to improve our understanding of these surface-atmosphere interactions based on the analysis of measurements carried out in Helsinki, Finland. The vertical exchange of momentum, heat, carbon dioxide (CO2) and aerosol particle number was measured with the eddy covariance technique at the urban measurement station SMEAR III, where the concentrations of ultrafine, accumulation mode and coarse particle numbers, nitrogen oxides (NOx), carbon monoxide (CO), ozone (O3) and sulphur dioxide (SO2) were also measured. These measurements were carried out over varying measurement periods between 2004 and 2008. In addition, black carbon mass concentration was measured at the Helsinki Metropolitan Area Council site during three campaigns in 1996-2005. Thus, the analyzed dataset covered far, the most comprehensive long-term measurements of turbulent fluxes reported in the literature from urban areas. Moreover, simultaneously measured urban air pollution concentrations and turbulent fluxes were examined for the first time. The complex measurement surrounding enabled us to study the effect of different urban covers on the exchange processes from a single point of measurement. The sensible and latent heat fluxes closely followed the intensity of solar radiation, and the sensible heat flux always exceeded the latent heat flux due to anthropogenic heat emissions and the conversion of solar radiation to direct heat in urban structures. This urban heat island effect was most evident during winter nights. The effect of land use cover was seen as increased sensible heat fluxes in more built-up areas than in areas with high vegetation cover. Both aerosol particle and CO2 exchanges were largely affected by road traffic, and the highest diurnal fluxes reached 109 m-2 s-1 and 20 µmol m-2 s-1, respectively, in the direction of the road. Local road traffic had the greatest effect on ultrafine particle concentrations, whereas meteorological variables were more important for accumulation mode and coarse particle concentrations. The measurement surroundings of the SMEAR III station served as a source for both particles and CO2, except in summer, when the vegetation uptake of CO2 exceeded the anthropogenic sources in the vegetation sector in daytime, and we observed a downward median flux of 8 µmol m-2 s-1. This work improved our understanding of the interactions between an urban surface and the atmosphere in a city located at high latitudes in a semi-continental climate. The results can be utilised in urban planning, as the fraction of vegetation cover and vehicular activity were found to be the major environmental drivers affecting most of the exchange processes. However, in order to understand these exchange and mixing processes on a city scale, more measurements above various urban surfaces accompanied by numerical modelling are required.