CHAPTER 4. THORPEX FIELD PROGRAMMES
4.3 UNIQUE THORPEX FIELD CAMPAIGN ADVANCEMENTS
As defined above, many THORPEX-related field campaigns addressed the utilization of
observations for improved prediction of high-impact weather. To facilitate the planning of adaptive observations during field programmes, the European Center for Medium range Weather
Forecasting (ECMWF) developed the Data Targeting System (DTS, Figure 11) as an interactive web-based system to allow users in different centres to participate in real-time adaptive control of the observing system with a minimum of manual effort. The DTS provided a facility to efficiently manage the data targeting process from weather event selection to issuing requests for additional observations, and has been used in several THORPEX field campaigns. The DTS enables users to a) identify potential high-impact weather events, in particular cases with large uncertainty; b)
request computation of sensitive areas (regions where additional observations are likely to have most impact in reducing the forecast uncertainty); c) identify and issue requests for additional real-time observations; and d) monitor the observation requests and confirm their subsequent deployment.
Field campaigns using the DTS have been able to issue requests for additional radiosonde ascents from 20 different participating countries, and for Aircraft Meteorological DAta Relay
(
AMDAR) aircraft observations and radiosondes from Automated Shipboard Aerological Programme (ASAP) ships participating in the EUCOS observing programme. In addition, the DTS has allowed users to identify sensitive areas for research aircraft observations. The DTS was used in a long-term quasi-operational trial (EURORISK PREVIEW) as well as in field campaigns, including summer and winter T-PARC, and most recently MEDEX and HyMeX campaigns to study the predictability of high-impact weather over the Mediterranean.An interactive three-dimensional (3D) visualization of ensemble weather predictions is a highly desired product for weather forecasting during aircraft-based atmospheric field campaigns.
Research flights with high-flying aircraft require the flight route to be planned several days in advance, hence, being able to assess the uncertainty of the forecast on which a flight is based is
very valuable. Since the targeted upper-level features are of an inherently three-dimensional nature, it seems natural to aid their identification with three-dimensional visualization methods. The
“Met.3D” system is a novel forecasting tool that makes recent advances in 3D and uncertainty visualization available to the forecaster (Figure 12). Interactive 2D and 3D visualization elements, displaying forecast meteorological fields and uncertainty measures derived from the ECMWF ensemble prediction system, enable the meteorologist to quickly identify atmospheric features relevant to a flight and to assess their uncertainty. The Met.3D was applied during the 2012 T-NAWDEX Falcon field campaign, a project that aimed at taking in-situ measurements in warm conveyor belts.
Figure 11. Schematic of the Data Targeting System definition of standard observation sensitivity areas placed along typical tropical cyclone paths over the western North Pacific.
Source: Figure supplied by D. Richardson
Figure 12. Met-3D display of the probability of a warm conveyor belt occurrence in advance of a developing cyclone over the North Sea. Grey shade indicates a 10% probability and the pink
shade represents a 30% probability.
Source: Figure by M. Rautenhaus
4.4 SUMMARY
The THORPEX-related field campaigns have led to study of factors and processes related to the forcing and predictability of high-impact weather over high-, mid-, and tropical latitudes. Throughout the 10 year period of THORPEX, field campaigns have been conducted over polar, midlatitude, and tropical regions. Additionally, several themed programmes served to provide frameworks for field programme planning, execution, and data analysis. Additionally, careful planning has been undertaken to maintain active and accessible data resources for many of the THORPEX-era field programmes. While all field programmes have not been included in this summary, those chosen represent the diverse topic, geographic, time, and spatial scales associated with all
THORPEX-related campaigns.
A significant aspect of the scientific success of THORPEX was to provide a framework by which communities in academia, laboratory, and operational forecasting could collaborate on research priorities with direct pathways to benefiting the entire process of weather forecasting. The field campaigns represent a unique aspect of that collaboration in which all of the communities became focused on specific hypotheses related to a particular physical process, modelling characteristics, and forecast problem.
Through THORPEX field campaigns, significant results were obtained in relation to processes related to high-impact weather over numerous regions of the tropics, midlatitudes, and poles. Many field programmes incorporated observing strategies, capabilities, and types that were never
attempted in the past. Improved understanding of processes and better representation of them in numerical models increased predictability of high-impact weather systems. Additionally, field programmes that provided means of obtaining special observations lead to analysis of the observation impact to forecasts. Important results identified sensitivities to numerical weather prediction systems and to the weather phenomenon itself. It is clear that a THORPEX legacy will be the scientific results attributed to field programmes and to the ability of field programmes to address THORPEX objectives related to the entire forecast process from 1-14 days.
REFERENCES
Bresson, E., V. Ducrocq, Nuissier, D., Ricard and C. De Saint-Aubin, 2012: Idealized numerical simulations of quasi-stationary convective systems over the Northwestern
Mediterranean complex terrain. Quarterly Journal of the Royal Meteorological Society, 138, 1750-1763.
Buzzi, A.S., P. Davoio, O. Malguzzi, D. Drofa and D. Mastrangelo, 2014: Heavy rainfall episodes over Liguria in autumn 2011: Numerical forecasting experiments. Natural Hazards and Earth System Sciences, 14, 1325-1340.
Chou, K.-H., C.-C. Wu, P.-H Lin, S.D. Aberson, M. Weissmann, F. Harnisch, T. Nakazawa, 2011:
The impact of dropwindsonde observations on typhoon track forecasts in DOTSTAR and T-PARC. Monthly Weather Revue, 139, 1728-1743.
Clark, P.A., K.A. Browning and C. Wang, 2005: The sting at the end of the tail: Model
diagnostics of fine-scale 3-D structure of the cloud head. Quarterly Journal of the Royal Meteorological Society, 131, 2263-2292.
Cohn, S.A., and collaborators, 2013: Driftsondes: Providing in situ long-duration dropsonde observations over remote regions. Bulletin of the American Meteorological Society, 94, 1661-1674.
Drobinski, P. and collaborators, 2014: HyMeX: a 10-year multidisciplinary Program on the Mediterranean water cycle. Bulletin of the American Meteorological Society, 95, 1063-1082.
Ducrocq, V., O. Nuissier, D. Ricard, C. Lebeaupin, S. Anquetin, 2008: A numerical study of three catastrophic precipitating events over southern France. II: Mesoscale triggering and stationarity factors, Quarterly Journal of the Royal Meteorological Society, 134, 131-145
Ducrocq, V. and collaborators, 2014: HyMeX-SOP1: The field campaign dedicated to heavy precipitation and flash flooding in the northwestern Mediterranean. Bulletin of the American Meteorological Society, 95, 1083-1100.
Duffourg, F. and V. Ducrocq, 2013: Assessment of the water supply to Mediterranean heavy precipitation : a method based on finely designed water budgets. Atmospheric Science Letters, 14(3), 133-138.
Foerster, A. M., M. M. Bell, P. A. Harr, and S. C. Jones, 2014: Observations of the eyewall structure of Typhoon Sinlaku (2008) during the transformation stage of extratropical transition. Monthly Weather Revue, 142, 3372-3392.
Hanesiak, J. M., and collaborators, 2010: Storm Studies in the Arctic (STAR), Bulletin of the American Meteorological Society, 91, 47-68.
Harnisch, F. and M. Weissmann, 2010: Sensitivity of typhoon forecasts to different subsets of targeted dropsonde observations. Monthly Weather Revue, 138, 2664-2680.
Irvine, E.A., S.L. Gray, J. Methven and I.A. Renfrew, 2011: Forecast impact of targeted observations: Sensitivity to observation error and proximity to steep orography.
Monthly Weather Revue, 139, 69-78.
Jansa, A., P. Alpert, P. Arbogast, A. Buzzi, B. Ivancan-Picek, V. Kotroni, M.C. Llasat, C. Ramis, E.
Richard, R. Romero and A. Speranza, 2014: MEDEX: A general overview. Natural Hazards and Earth System Sciences, 14, 1965-1984.
Keller, J.H., S.C. Jones, J.L. Evans and P.A. Harr, 2011: Representation of Extratropical Transition in the new TIGGE multi model ensemble prediction system. Geophysical Research Letters, 38, L12801.
Kristjànsson, J., and collaborators, 2011: The Norwegian IPY-THORPEX: Polar lows and arctic fronts during the 2008 Andoya Campaign. Bulletin of the American Meteorological Society, 92, 1443-1466.
Norden, T.E., G. Brunet and J. Caughney, 2007: Improvements of weather forecasts in polar regions. WMO Bulletin, 56(4), 250-256.
Nuissier, O., B. Joly, A. Joly, V. Ducrocq and P. Arbogast, 2011: A statistical downscaling to identify the large-scale circulation patterns associated with heavy precipitation events over southern France. Quarterly Journal of the Royal Meteorological Society, 137, 1657-1932, doi: 10.1002/qj.866.
Petersen, G.N., I.A. Renfrew and G.W.K. Moore, 2009: An overview of barrier winds off southeastern Greenland during GFDex. Quarterly Journal of the Royal Meteorological Society, 135, 1950-1967.
Quinting, J.F., M.M. Bell, P.A. Harr and S.C. Jones, 2014: Structural characteristics of T-PARC Typhoon Sinlaku during its extratropical transition. Monthly Weather Revue, 142, 1945-1961.
Rabier, F., and collaborators, 2013: The Concordiasi field experiment over Antarctica: First results from innovative atmospheric measurements. Bulletin of the American Meteorological Society, 94, ES17-ES20.
Ricard, D., V. Ducrocq, and L Auger, 2012: A climatology of the mesoscale environment associated with heavily precipitating events over a northwestern Mediterranean area, Journal of Applied Meteorology and Climatology, 51,468-488,
doi:10.1175/JAMC-D-11-017.1.
Sanabia, E.R., 2010: The Re-intensification of Typhoon Sinlaku (2008). PhD Dissertation, Naval Postgraduate School, Monterey, CA 93943, 213pp. [Available at:
http://edocs.nps.edu/npspubs/scholarly/dissert/2010/Jun/10Jun_sanabia_phd.pdf]
Vaughan, G., and collaborators, 2015: Cloud banding and winds in intense European cyclones:
Results from the DIAMET Project. Bulletin of the American Meteorological Society, in press.
Waliser, D.E., and collaborators, 2012: The “Year” of Tropical Convection (May 2008-April 2010): Climate variability and weather highlights. Bulletin of the American
Meteorological Society, 93, 1189-1218.
Weissmann, M., F. Harnisch, C.C. Wu, P.H. Lin, Y. Ohta, K. Yamashita, Y.H. Kim, E.H. Jeon, T. Nakazawa and S. Aberson, 2011: The influence of assimilating dropsonde data on typhoon track and mid-latitude forecasts. Monthly Weather Revue, 139, 908-920.
Wu, C.-C., Y.-H Huang and G.-Y. Lien, 2012: Concentric eyewall formation in Typhoon Sinlaku (2008). Part I: Assimilation of T-PARC data based on the ensemble Kalman filter (EnKF). Monthly Weather Revue, 140, 506-527.
Wu. C.-C., S.-G. Chen, C.-C. Yang, P.-H. Lin and S.D. Aberson, 2012: Potential vorticity diagnosis of the factors affecting track of Typhoon Sinlaku (2008) and the impact from dropwindsonde data during T-PARC. Monthly Weather Revue, 140, 2670-2688.
Wu, C.-C., S.-G. Chen, S.-C. Lin, T.-H. Yen and T.-C. Chen, 2013: Uncertainty and
predictability of tropical cyclone rainfall based on ensemble simulations of Typhoon Sinlaku (2008). Monthly Weather Revue, 141, 3517-3538.
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CHAPTER 5. DYNAMICS AND PREDICTABILITY OF MIDDLE LATITUDE