Search Results
and Ágústsson 2009 ; Lane et al. 2009 ; Sharman et al. 2012a ). Greenland is of particular importance as it is located underneath the highly frequented North Atlantic flight tracks connecting Europe and North America. The Graphical Turbulence Guidance (GTG) product provides automated, aircraft-type-independent turbulence forecasts for CAT and MWT at all flight levels (FL) from surface to the lower stratosphere (FL500; “500” indicates 50 000 ft, with 1 ft ≈ 0.3 m) ( Sharman et al. 2006 ; Sharman
and Ágústsson 2009 ; Lane et al. 2009 ; Sharman et al. 2012a ). Greenland is of particular importance as it is located underneath the highly frequented North Atlantic flight tracks connecting Europe and North America. The Graphical Turbulence Guidance (GTG) product provides automated, aircraft-type-independent turbulence forecasts for CAT and MWT at all flight levels (FL) from surface to the lower stratosphere (FL500; “500” indicates 50 000 ft, with 1 ft ≈ 0.3 m) ( Sharman et al. 2006 ; Sharman
shown in Fig. 1 (bottom). Figure 2 shows the extent of all DEEPWAVE measurements in altitude and latitude. F ig . 2. North–south cross section showing the types of airborne and ground-based instruments contributing to DEEPWAVE measurements and their coverage in latitude and altitude. DEEPWAVE began with a test flight-planning exercise from 1 to 10 August 2013 to gain experience with forecasting and flight planning and to assess the reliability of such forecasts in preparation for the real field
shown in Fig. 1 (bottom). Figure 2 shows the extent of all DEEPWAVE measurements in altitude and latitude. F ig . 2. North–south cross section showing the types of airborne and ground-based instruments contributing to DEEPWAVE measurements and their coverage in latitude and altitude. DEEPWAVE began with a test flight-planning exercise from 1 to 10 August 2013 to gain experience with forecasting and flight planning and to assess the reliability of such forecasts in preparation for the real field
second section, we describe the research aircraft and its instruments dedicated to the measurements of GW properties, along with the ground based measurements in the region. We will introduce the forecast model tools used for flight planning as well as reanalysis fields which are being used for the interpretation of atmospheric measurements. In the third section, we describe the prevailing meteorological conditions under which the flights were conducted. Mission overview and initial promising results
second section, we describe the research aircraft and its instruments dedicated to the measurements of GW properties, along with the ground based measurements in the region. We will introduce the forecast model tools used for flight planning as well as reanalysis fields which are being used for the interpretation of atmospheric measurements. In the third section, we describe the prevailing meteorological conditions under which the flights were conducted. Mission overview and initial promising results
reduce uncertainties related to the parameterization of GWs is severely hindered by a lack of observational constraints. A single instrument or technique can only observe a certain part of the GW spectrum ( Alexander et al. 2010 ; Geller et al. 2013 ). In addition, the synthesis of available data is insufficient to construct a global reference for GW properties. In fact, many assumptions of GW parameterizations are derived from regional cloud-resolving simulations with grid spacings sufficiently
reduce uncertainties related to the parameterization of GWs is severely hindered by a lack of observational constraints. A single instrument or technique can only observe a certain part of the GW spectrum ( Alexander et al. 2010 ; Geller et al. 2013 ). In addition, the synthesis of available data is insufficient to construct a global reference for GW properties. In fact, many assumptions of GW parameterizations are derived from regional cloud-resolving simulations with grid spacings sufficiently
. Data sources Operational analyses of the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) are used to provide meteorological data to characterize the atmospheric situation. The 6-hourly operational analysis and hourly forecast fields of the IFS cycle 40r1 have a horizontal resolution on the reduced linear Gaussian grid of about 16 km (T L 1279) and 137 vertical model levels (L137) from the ground to ~80 km (0.01 hPa) with layer thicknesses gradually
. Data sources Operational analyses of the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) are used to provide meteorological data to characterize the atmospheric situation. The 6-hourly operational analysis and hourly forecast fields of the IFS cycle 40r1 have a horizontal resolution on the reduced linear Gaussian grid of about 16 km (T L 1279) and 137 vertical model levels (L137) from the ground to ~80 km (0.01 hPa) with layer thicknesses gradually
higher altitudes (e.g., Siskind 2014 ). Thereby, the wind field and the thermal structure of the middle atmosphere are modified (e.g., Lindzen 1981 ; Holton and Alexander 2000 ). Internal gravity waves have been measured and analyzed with a large variety of active and passive remote sensing techniques as well as with in situ observations. These observational tools include airborne and ground-based lidars (e.g., Alexander et al. 2011 ; Dörnbrack et al 2002 ; Rauthe et al. 2008 ; Williams et al
higher altitudes (e.g., Siskind 2014 ). Thereby, the wind field and the thermal structure of the middle atmosphere are modified (e.g., Lindzen 1981 ; Holton and Alexander 2000 ). Internal gravity waves have been measured and analyzed with a large variety of active and passive remote sensing techniques as well as with in situ observations. These observational tools include airborne and ground-based lidars (e.g., Alexander et al. 2011 ; Dörnbrack et al 2002 ; Rauthe et al. 2008 ; Williams et al
analyses valid at 0000, 0600, 1200, and 1800 UTC and 1-hourly high-resolution forecasts at intermediate lead times (+1, +2, +3, +4, +5, +7, +8, +9, +10, and +11 h) of the 0000 and 1200 UTC forecast runs of the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) are further used to visualize the temporal evolution of the upstream conditions at 44.20°S, 167.50°E ( Fig. 1 ). The IFS cycle 40r1 has a horizontal resolution of about 16 km, 137 vertical model
analyses valid at 0000, 0600, 1200, and 1800 UTC and 1-hourly high-resolution forecasts at intermediate lead times (+1, +2, +3, +4, +5, +7, +8, +9, +10, and +11 h) of the 0000 and 1200 UTC forecast runs of the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) are further used to visualize the temporal evolution of the upstream conditions at 44.20°S, 167.50°E ( Fig. 1 ). The IFS cycle 40r1 has a horizontal resolution of about 16 km, 137 vertical model
European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS), for nonorographic gravity waves, the amplitude at source level is set to a globally uniform value and adjusted by a prescribed relation for latitude and resolution (see section 5.3 in ECMWF 2018 ). This is a gross simplification of spatial variability and the complete neglect of temporal variability in the wave emission process. Following earlier work by Zülicke and Peters (2008) , a new approach to
European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS), for nonorographic gravity waves, the amplitude at source level is set to a globally uniform value and adjusted by a prescribed relation for latitude and resolution (see section 5.3 in ECMWF 2018 ). This is a gross simplification of spatial variability and the complete neglect of temporal variability in the wave emission process. Following earlier work by Zülicke and Peters (2008) , a new approach to
-hourly atmospheric variables from the European Centre for Medium-Range Weather Forecasts interim reanalysis (ERA-Interim, hereafter ERA-I; Dee et al. 2011 ) are used. The ERA-I data used have a horizontal resolution of 2.5° × 2.5°. We make use of the following ERA-I fields: horizontal winds ( u and υ ), and geopotential height ( z ) at low-level (850 hPa) and upper-level troposphere (200 hPa). The horizontal winds are also used to calculate velocity potential ( χ ) as the inverse Laplacian of the
-hourly atmospheric variables from the European Centre for Medium-Range Weather Forecasts interim reanalysis (ERA-Interim, hereafter ERA-I; Dee et al. 2011 ) are used. The ERA-I data used have a horizontal resolution of 2.5° × 2.5°. We make use of the following ERA-I fields: horizontal winds ( u and υ ), and geopotential height ( z ) at low-level (850 hPa) and upper-level troposphere (200 hPa). The horizontal winds are also used to calculate velocity potential ( χ ) as the inverse Laplacian of the
, 2006a : Fourier-ray modeling of short-wavelength trapped lee waves observed in infrared satellite imagery near Jan Mayen . Mon. Wea. Rev. , 134 , 2830 – 2848 , https://doi.org/10.1175/MWR3218.1 . 10.1175/MWR3218.1 Eckermann , S. D. , A. Dörnbrack , H. Flentje , S. B. Vosper , M. J. Mahoney , T. P. Bui , and K. S. Carslaw , 2006b : Mountain wave–induced polar stratospheric cloud forecasts for aircraft science flights during SOLVE/THESEO 2000 . Wea. Forecasting , 21 , 42
, 2006a : Fourier-ray modeling of short-wavelength trapped lee waves observed in infrared satellite imagery near Jan Mayen . Mon. Wea. Rev. , 134 , 2830 – 2848 , https://doi.org/10.1175/MWR3218.1 . 10.1175/MWR3218.1 Eckermann , S. D. , A. Dörnbrack , H. Flentje , S. B. Vosper , M. J. Mahoney , T. P. Bui , and K. S. Carslaw , 2006b : Mountain wave–induced polar stratospheric cloud forecasts for aircraft science flights during SOLVE/THESEO 2000 . Wea. Forecasting , 21 , 42
