VORTICITY BUDGET OVER MOUNTAINS, DIAGNOSED FROM HIRLAM ANALYSES AND FORECASTS

The analysis of vorticity equation offers a possibility for validation and diagnostics of a NWP model. The source terms of the equation are related to the resolved and subgrid-scale torque due to the orography and surface properties. The terms resolved by the model can be estimated from three-dimensional numerical analyses and forecasts. In the vertically integrated equation, these terms sum up to give an estimate of required torque due to the subgrid-scale surface stress, which can be compared by the corresponding value given by the physical parametrizations of the model. Diagnosis of the complicated terms of the equation requires special attention to the discretization and numerical approximations. In this study, the vorticity method is applied to the diagnosis of High Resolution Limited Area Model (HIRLAM)

"Se tuo sellaista väriä ja räiskyvyyttä arkeen" : Maijalanpuiston päiväkodin henkilökunnan kokemuksia monikulttuurisuuskasvatuksesta

Opinnäytetyön tavoitteena oli tutkia monikulttuurisuuskasvatusta Maijalanpuiston päiväkodin henkilökunnan kokemana. Opinnäytetyössä tutkittiin, minkälaisia käsityksiä Maijalanpuiston henkilökunnalla oli monikulttuurisuuskasvatuksesta yleensä sekä kuinka he toteuttavat monikulttuurisuuskasvatusta päiväkodin jokapäiväisessä arjessa. Tutkimuksessa selvitettiin myös Maijalanpuistossa hyvin toimivia asioita sekä haasteita liittyen monikulttuurisuuskasvatukseen. Opinnäytetyö toteutettiin kvalitatiivisena tutkimuksena. Tutkimusmenetelmänä oli teemahaastattelu, joka suoritettiin ryhmähaastatteluina. Yhteensä haastateltavia oli yhdeksän, joista osa oli lastentarhanopettajia ja osa lastenhoitajia. Aineiston analyysimenetelmänä oli teemoittelu. Aineiston perusteella monikulttuurisuuskasvatus miellettiin usein tavalliseksi arjeksi, jossa otetaan huomioon lasten erilaiset taustat sekä taustojen erilaisuuteen liittyvät haasteet. Monikulttuurisuuskasvatus koettiin Maijalanpuistossa perustyöksi, eivätkä haastateltavat kokeneet jatkuvasti toteuttavansa monikulttuurisuuskasvatusta. Suomen kielen opetuksen rooli oli merkittävä. Monikulttuurisuuskasvatus toi mukanaan useita haasteita, mutta niistä huolimatta se koettiin positiiviseksi asiaksi. Monikulttuurisuuskasvatus on Suomessa vielä verrattain uusi asia, joten sitä voisi tuoda vielä enemmän näkyväksi päiväkotien arjessa. Myös varhaiskasvatuksen koulutukseen kaivataan monikulttuurisuusopintoja.The objective of this study was to investigate the Maijalanpuisto kindergarten staff’s perceptions of multicultural education and how they do it in practice in the kindergarten. The study also aimed to find out the staff’s opinions of what had succeeded in multicultural education and what still had to be developed there. This was a qualitative study. The data was collected in theme interviews. Altogether nine persons were interviewed in groups that consisted of both kindergarten teachers and nursery nurses. The analysis method was thematising. The results indicate that multicultural education is usually seen as part of everyday life and the basic routines of the kindergarten, where children’s different backgrounds are taken into account without considering it specifically multicultural education. The teaching of Finnish had a big role. Multicultural education was felt to be challenging, but the experiences were positive. Multicultural education is quite new in Finland, and it could be made more visible in kindergartens. The kindergarten staff also wished for more multicultural education studies in early education study programs

Studies on orographic effects in a numerical weather prediction model

Numerical models, used for atmospheric research, weather prediction and climate simulation, describe the state of the atmosphere over the heterogeneous surface of the Earth. Several fundamental properties of atmospheric models depend on orography, i.e. on the average elevation of land over a model area. The higher is the models' resolution, the more the details of orography directly influence the simulated atmospheric processes. This sets new requirements for the accuracy of the model formulations with respect to the spatially varying orography. Orography is always averaged, representing the surface elevation within the horizontal resolution of the model. In order to remove the smallest scales and steepest slopes, the continuous spectrum of orography is normally filtered (truncated) even more, typically beyond a few gridlengths of the model. This means, that in the numerical weather prediction (NWP) models, there will always be subgridscale orography effects, which cannot be explicitly resolved by numerical integration of the basic equations, but require parametrization. In the subgrid-scale, different physical processes contribute in different scales. The parametrized processes interact with the resolved-scale processes and with each other. This study contributes to building of a consistent, scale-dependent system of orography-related parametrizations for the High Resolution Limited Area Model (HIRLAM). The system comprises schemes for handling the effects of mesoscale (MSO) and small-scale (SSO) orographic effects on the simulated flow and a scheme of orographic effects on the surface-level radiation fluxes. Representation of orography, scale-dependencies of the simulated processes and interactions between the parametrized and resolved processes are discussed. From the high-resolution digital elevation data, orographic parameters are derived for both momentum and radiation flux parametrizations. Tools for diagnostics and validation are developed and presented. The parametrization schemes applied, developed and validated in this study, are currently being implemented into the reference version of HIRLAM.Ilmakehätutkimukseen sekä sään ja ilmaston ennustamiseen käytettävät numeeriset mallit kuvaavat ilmakehän tilaa maapallon vaihtelevien pinnanmuotojen yllä. Monet mallin perusominaisuuksista riippuvat orografiasta eli maanpinnan korkeuden kuvauksesta. Mitä tarkempi on mallin erotuskyky, sitä pienemmät orografian yksityiskohdat vaikuttavat mallinnettuihin ilmakehän ominaisuuksiin. Tämä asettaa uusia vaatimuksia sille, miten malli käsittelee orografiatietoa. Orografia on aina keskiarvo, joka kuvaa pinnan korkeutta mallin erotuskyvyn puitteissa. Mallin perusyhtälöt eivät pysty suoraan käsittelemään kaikkia orografian yksityiskohtia. Siksi muutamaa mallin hilaväliä pienemmät piirteet tavallisesti suodatetaan pois. Numeeriseen säänennustusmalliin jää aina alihilaisen orografian aiheuttamia ilmiöitä, jotka pitää kuvata parametrisoimalla, t.s. perusyhtälöiden lähde- ja nielutermien avulla. Alihilaiset piirteet ovat erikokoisia ja niiden fysikaaliset ominaisuudet erilaisia. Parametrisoidut ilmiöt vuorovaikuttavat toistensa ja mallissa suoraan kuvattujen ilmiöiden kanssa. Tässä tutkimuksessa on kehitetty mallin erotuskyvyn ja orografian koon huomioonottavaa pinnanmuotovaikutusten parametrisointijärjestelmää pohjoismaista HIRLAM-säänennustusmallia (High Resolution Limited Area Model) varten. Järjestelmä koostuu meso- ja pienimittaisen orogafian vaikutusten parametrisoinnista mallin liikeyhtälöissä sekä maanpinnan tason lyhyt- ja pitkäaaltosäteilyvoiden parametrisoinnista lämpötilayhtälössä. Työssä käsitellään orografian kuvausta, mallinnuksen skaalariippuvuuksia sekä prosessien vuorovaikutuksia. Mallin orografiasuureet johdetaan tarkasta digitaalisesta karttatiedosta sekä liikemäärän että säteilyvoiden laskentaa varten Työssä kehitellään myös menetelmiä mallitulosten todentamista ja analysointia varten. Työssä kehiteltyjä, sovellettuja ja arvioituja menetelmiä otetaan parhaillaan päivittäiseen ennustuskäyttöön HIRLAM-mallissa

Renewal of aerosol data for ALADIN-HIRLAM radiation parametrizations

Número monográfico dedicado al "18th EMS Annual Meeting: European Conference for Applied Meteorology and Climatology 2018"Radiative transfer calculations in numerical weather prediction (NWP) and climate models require reliable information about aerosol concentration in the atmosphere, combined with data on aerosol optical properties. Replacement of the default input data on vertically integrated climatological aerosol optical depth at 550 nm (AOD550, Tegen climatology) with newer data, based on those available from Copernicus atmosphere monitoring service (CAMS), led to minor differences in the simulated solar irradiance and screen-level temperature in the regional climate model HCLIM-ALARO simulations over Scandinavia and in a clear-sky case study using HARMONIE-AROME NWP model over the Iberian peninsula. In the case study, replacement of the climatological AOD550 with that based on three-dimensional near-real-time aerosol mass mixing ratio resulted in a maximum reduction of the order of 150 W m−2 in the simulated local solar irradiance at noon. Corresponding maximum reduction of the screen-level temperature by almost two degrees was found. The large differences were due to a dust intrusion from Sahara, which is obviously not represented in the average climatological distribution of dust aerosol. Further studies are needed in order to introdude updated aerosol optical properties of all available aerosol types at different wavelengths, make them available for the radiation schemes of ALADIN-HIRLAM and test the impact on the predicted radiation fluxes

Sensitivity of radiative fluxes to aerosols in the ALADIN-HIRLAM numerical weather prediction system

The direct radiative effect of aerosols is taken into account in many limited-area numerical weather prediction models using wavelength-dependent aerosol optical depths of a range of aerosol species. We studied the impact of aerosol distribution and optical properties on radiative transfer, based on climatological and more realistic near real-time aerosol data. Sensitivity tests were carried out using the single-column version of the ALADIN-HIRLAM numerical weather prediction system, set up to use the HLRADIA simple broadband radiation scheme. The tests were restricted to clear-sky cases to avoid the complication of cloud–radiation–aerosol interactions. The largest differences in radiative fluxes and heating rates were found to be due to different aerosol loads. When the loads are large, the radiative fluxes and heating rates are sensitive to the aerosol inherent optical properties and the vertical distribution of the aerosol species. In such cases, regional weather models should use external real-time aerosol data for radiation parametrizations. Impacts of aerosols on shortwave radiation dominate longwave impacts. Sensitivity experiments indicated the important effects of highly absorbing black carbon aerosols and strongly scattering desert dust

The HIRLAM fast radiation scheme for mesoscale numerical weather prediction models

This paper provides an overview of the HLRADIA shortwave (SW) and longwave (LW) broadband radiation schemes used in the HIRLAM numerical weather prediction (NWP) model and available in the HARMONIE-AROME mesoscale NWP model. The advantage of broadband, over spectral, schemes is that they can be called more frequently within the model, without compromising on computational efficiency. In mesoscale models fast interactions between clouds and radiation and the surface and radiation can be of greater importance than accounting for the spectral details of clear-sky radiation; thus calling the routines more frequently can be of greater benefit than the deterioration due to loss of spectral details. Fast but physically based radiation parametrizations are expected to be valuable for high-resolution ensemble forecasting, because as well as the speed of their execution, they may provide realistic physical perturbations. Results from single-column diagnostic experiments based on CIRC benchmark cases and an evaluation of 10 years of radiation output from the FMI operational archive of HIRLAM forecasts indicate that HLRADIA performs sufficiently well with respect to the clear-sky downwelling SW and longwave LWfluxes at the surface. In general, HLRADIA tends to overestimate surface fluxes, with the exception of LW fluxes under cold and dry conditions. The most obvious overestimation of the surface SW flux was seen in the cloudy cases in the 10-year comparison; this bias may be related to using a cloud inhomogeneity correction, which was too large. According to the CIRC comparisons, the outgoing LW and SW fluxes at the top of atmosphere are mostly overestimated by HLRADIA and the net LW flux is underestimated above clouds. The absorption of SW radiation by the atmosphere seems to be underestimated and LW absorption seems to be overestimated. Despite these issues, the overall results are satisfying and work on the improvement of HLRADIA for the use in HARMONIE-AROME NWP system is ongoing. In a HARMONIE-AROME 3-D forecast experiment we have shown that the frequency of the call for the radiation parametrization and choice of the parametrization scheme makes a difference to the surface radiation fluxes and changes the spatial distribution of the vertically integrated cloud cover and precipitation.Peer reviewe

Snow and ice on Bear Lake (Alaska) - sensitivity experiments with two lake ice models

Peer reviewe

Modelling experiments on air–snow–ice interactions over Kilpisjärvi, a lake in northern Finland

The evolution of snow and ice thicknesses and temperature in an Arctic lake was investigated using two models: a high-resolution, time-dependent model (HIGHTSI) and a quasi-steady two-layer model on top of a lake model (FLake). In situ observations and a Numerical Weather Prediction model (HIRLAM) were used for the forcing data. HIRLAM forecasts, after orography correction, were comparable with the in situ data. Both lake-ice models predicted the ice thickness (accuracy 5 cm), surface temperature (accuracy 2–3 °C in winter, better in spring), and ice-breakup date (accuracy better than five days) well. HIGHTSI was better for ice thickness and ice-breakup date, while FLake gave better freezing date. Snow thickness outcome was worse, in particular for the melting season. Surface temperature was highly sensitive to air temperature, stratification and albedo, and the largest errors (positively biased) resulted in strongly stable conditions