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Ljungemyr, Patrik
Publikationer (4 of 4) Visa alla publikationer
Hordoir, R., Axell, L., Höglund, A., Dieterich, C., Fransner, F., Groger, M., . . . Haapala, J. (2019). Nemo-Nordic 1.0: a NEMO-based ocean model for the Baltic and North seas - research and operational applications. Geoscientific Model Development, 12(1), 363-386
Öppna denna publikation i ny flik eller fönster >>Nemo-Nordic 1.0: a NEMO-based ocean model for the Baltic and North seas - research and operational applications
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2019 (Engelska)Ingår i: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 12, nr 1, s. 363-386Artikel i tidskrift (Refereegranskat) Published
Nationell ämneskategori
Oceanografi, hydrologi och vattenresurser
Identifikatorer
urn:nbn:se:smhi:diva-5159 (URN)10.5194/gmd-12-363-2019 (DOI)000456302000003 ()
Tillgänglig från: 2019-02-05 Skapad: 2019-02-05 Senast uppdaterad: 2019-02-05Bibliografiskt granskad
Golbeck, I., Li, X., Janssen, F., Bruening, T., Nielsen, J. W., Huess, V., . . . Axell, L. (2015). Uncertainty estimation for operational ocean forecast products-a multi-model ensemble for the North Sea and the Baltic Sea. Ocean Dynamics, 65(12), 1603-1631
Öppna denna publikation i ny flik eller fönster >>Uncertainty estimation for operational ocean forecast products-a multi-model ensemble for the North Sea and the Baltic Sea
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2015 (Engelska)Ingår i: Ocean Dynamics, ISSN 1616-7341, E-ISSN 1616-7228, Vol. 65, nr 12, s. 1603-1631Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Multi-model ensembles for sea surface temperature (SST), sea surface salinity (SSS), sea surface currents (SSC), and water transports have been developed for the North Sea and the Baltic Sea using outputs from several operational ocean forecasting models provided by different institutes. The individual models differ in model code, resolution, boundary conditions, atmospheric forcing, and data assimilation. The ensembles are produced on a daily basis. Daily statistics are calculated for each parameter giving information about the spread of the forecasts with standard deviation, ensemble mean and median, and coefficient of variation. High forecast uncertainty, i.e., for SSS and SSC, was found in the Skagerrak, Kattegat (Transition Area between North Sea and Baltic Sea), and the Norwegian Channel. Based on the data collected, longer-term statistical analyses have been done, such as a comparison with satellite data for SST and evaluation of the deviation between forecasts in temporal and spatial scale. Regions of high forecast uncertainty for SSS and SSC have been detected in the Transition Area and the Norwegian Channel where a large spread between the models might evolve due to differences in simulating the frontal structures and their movements. A distinct seasonal pattern could be distinguished for SST with high uncertainty between the forecasts during summer. Forecasts with relatively high deviation from the multi-model ensemble (MME) products or the other individual forecasts were detected for each region and each parameter. The comparison with satellite data showed that the error of the MME products is lowest compared to those of the ensemble members.

Nationell ämneskategori
Oceanografi, hydrologi och vattenresurser
Forskningsämne
Oceanografi
Identifikatorer
urn:nbn:se:smhi:diva-1937 (URN)10.1007/s10236-015-0897-8 (DOI)000365876400002 ()
Tillgänglig från: 2016-04-29 Skapad: 2016-03-03 Senast uppdaterad: 2018-01-10Bibliografiskt granskad
Funquist, L. & Ljungemyr, P. (1997). Validation of HIROMB during 1995-96. SMHI
Öppna denna publikation i ny flik eller fönster >>Validation of HIROMB during 1995-96
1997 (Engelska)Rapport (Övrigt vetenskapligt)
Ort, förlag, år, upplaga, sidor
SMHI, 1997. s. 16
Serie
Oceanografi, ISSN 0283-7714 ; 67
Nyckelord
HIROMB, HIROMB
Identifikatorer
urn:nbn:se:smhi:diva-2528 (URN)Oceanografi, Rapporter, Serie Oceanografi (Lokalt ID)Oceanografi, Rapporter, Serie Oceanografi (Arkivnummer)Oceanografi, Rapporter, Serie Oceanografi (OAI)
Tillgänglig från: 1997-05-15 Skapad: 2016-07-08 Senast uppdaterad: 2016-07-08Bibliografiskt granskad
Ljungemyr, P., Gustafsson, N. & Omstedt, A. (1996). Parameterization of lake thermodynamics in a high-resolution weather forecasting model. Paper presented at 1st Study Conference on BALTEX, AUG 28-SEP 01, 1995, VISBY, SWEDEN. Tellus. Series A, Dynamic meteorology and oceanography, 48(5), 608-621
Öppna denna publikation i ny flik eller fönster >>Parameterization of lake thermodynamics in a high-resolution weather forecasting model
1996 (Engelska)Ingår i: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 48, nr 5, s. 608-621Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

A model for the parameterization of lake temperatures and lake ice thicknesses in atmospheric models is presented. The model is verified independently, and it is also tested within the framework of the High Resolution Limited Area Model(HIRLAM), applied operationally for short range weather forecasting at the Swedish Meteorological and Hydrological Institute (SMHI). The lake model is a slab model based upon energy conservation and treats the lakes as well mixed boxes with depths represented by the mean depths. The model is forced by near surface fluxes calculated from total cloudiness, air temperature, air humidity and low-level winds. A data base, describing 92000 Swedish lakes. provides the model with lake mean depths, areal sizes and locations. When the model is used for parameterization of lake effects in the atmospheric model, all the smaller lakes and the fractions of larger lakes within each horizontal grid square of the atmospheric model are parameterized by four model lakes, representing the lake size distribution. The verification of the lake model is done by comparing it with a more advanced, vertically resolved model, including parameterization of turbulent mixing processes, as well as by comparison with observations. A sensitivity test shows great interannual variations of the ice-covered season, which implies that lake models should be used instead of climate data. The results from an experiment with two-way coupling of the lake model to the atmospheric model are verified by comparing forecasted weather parameters with routine meteorological observations. These results show that the impact of lake effects can reach several degrees C in air temperatures close to the surface.

Nationell ämneskategori
Oceanografi, hydrologi och vattenresurser
Forskningsämne
Hydrologi
Identifikatorer
urn:nbn:se:smhi:diva-1629 (URN)10.1034/j.1600-0870.1996.t01-4-00002.x (DOI)A1996VV42600002 ()
Konferens
1st Study Conference on BALTEX, AUG 28-SEP 01, 1995, VISBY, SWEDEN
Tillgänglig från: 2016-01-26 Skapad: 2015-12-22 Senast uppdaterad: 2018-05-24
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