Identify and interpret fields and derived products
Zorana Jelenak describes how altimeters work, how data is used for everyday marine forecasting at NOAA and assimilation.
Length: 60 min
Author: Zorana Jelenak (NOAA)
Altimeter data have been used to produce maps of sea surface height, geostrophic velocity, significant wave height and wind speed. This information is of proven use to mariners as well as to the scientific community. Uses of the data include commercial and recreational vessel routing, ocean acoustics, input to geographic information systems developed for the fishing industry, identification of marine mammal habitats, fisheries management and monitoring ocean debris. Such information is accessible in near-real time (within 3 to 48 hours) and to improve weather forecasting models by assimilation. 25 years of data makes it possible to study the whole ocean or regional areas for offshore industries or navigation. In hurricane studies altimetry measures very high waves and strong winds, but also helps identify sea surface height anomalies which can be used as proxies of the warm currents - hurricanes energy source. The lecture will describe how altimeters work, how data is used for everyday marine forecasting at NOAA and assimilation, devoteting special attention to data accuracy and limitations.
Jean Bidlot gives an overview on the ECMWF wave model products.
Length: 50 min
Author: Jean Bidlot (ECMWF)
Wave models are able to give a very detailed description of the conditions at the surface of the oceans. The mean sea state is fully described by the 2d wave spectrum. This detailed description is however not always very practical and the bulk of the information contained in the 2d spectrum is usually reduced in the form of a set of integrated parameters, from a simple few such as significant wave height, mean wave direction and mean wave period, to more sophisticated parameters that described distinct part of the wave fields. Recent advances in the understanding of wave dynamics have lead to the development of new set of parameters that give information on the possible largest single wave that might exist over a certain area within a certain time frame. It is now possible to describe the sea state with different level of complexity depending on the user needs.
Michael Folmer presents examples of relevant applications of Sentinel-3A data.
Length: 55 min
Author: Michael Folmer (NOAA)
The EUMETSAT-operated Copernicus Sentinel-3A satellite has been providing near-real time data to the marine community since mid-2016, and will be soon be joined in operations by its sister, Sentinel-3B. This presentation will give an overview of the available Sentinel-3 marine products, with a primary focus on data streams associated by the altimeter (SRAL) and sea surface temperature radiometer (SLSTR). Examples of the relevant applications will be presented, along with a discussion of how users can best access data and monitor its quality.
Ad Stoffelen focuses on scatterometer winds, how good they are and what aspects need attention.
Length: 60 min
Author: Ad Stoffelen (KNMI)
Winds over sea are essential for marine forecasting and used in nowcasting and numerical weather prediction (NWP) to aid in off-shore activities (energy sector, transport, fisheries and recreation), particularly to secure safety of life and property. Winds over sea are observed by satellites and available from NWP model forecasts. Most satellite winds over sea are provided by scatterometers; they provide swath fields of both wind speed and wind direction from polar satellites. Currently, winds from EUMETSAT’s MetOp-A, MetOpB and the Indian ScatSat-1 are operationally available and provide good coverage around 9:00 and 21:00 local solar time (LST). Very soon they will be complemented by a few more. The lecture focuses on what scatterometer winds really represent, how good they are and what aspects need attention when applying these winds in your routine operations alongside with NWP model winds.
Thomas August gives an introduction to EUMETSATs current (IASI) and future (IASI-NG and MTG-S) hyperspectral sounders.
Length: 46 minutes.
Assessing and monitoring atmospheric thermodynamic parameters is key for weather forecasting. Space-borne hyperspectral sounders provide vertically resolved information of atmospheric temperature and humidity, and of surface and cloud properties. The future geostationary infrared sounder IRS on board Meteosat Third Generation (MTG) will deliver operational atmospheric sounding at unprecedented temporal and spatial sampling, with 4-km pixels at Nadir and covering Europe every 30 minutes. It will hence be an important complement to satellite imagery (e.g. operational MSG/SEVIRI or the future MTG/FCI instruments), where long experience exist in support to nowcasting, by allowing the detection and monitoring of atmospheric instabilities before convective clouds develop.
In this presentation, we give an introduction to EUMETSAT current (IASI) and future (IASI-NG and MTG-IRS) hyperspectral sounders, the remote-sensing principles and geophysical information contained in the so-called Level 2 (L2) products. This includes temperature and humidity profiles, cloud and surface properties and indirect parameters relating to the atmospheric stability. We give an overview of recent application studies and experiments using IASI L2 products in support to weather forecasting.
Pieter Groenemeijer reports of the tests ESSL has undertaken to check the usability of ISAI L2 temperature and humidity profiles in storm forecasting.
Length: 44 minutes.
ESSL studied the use of retrieved temperature and humidity profiles available from the Infrared Atmospheric Sounding Interferometer (IASI) instrument on the polar-orbiting Metop satellites for storm forecasting during the 2019 Testbed and for a number of cases. Parameters relevant to convective storm prediction such as CAPE, CIN and humidity at various levels were computed and a direct visual comparison between the satellite-derived and NWP-modelled profiles was made possible. We present the main conclusions of this study, addressing the usability of the products, preferred derived parameters and observed limitations.
Thomas August provides an overview of the performances of the operational hyperspectral sounding products.
Length: 34 minutes.
In this presentation, we provide an overview of the performances of the operational hyperspectral sounding products. They have been evaluated against independent reference measurements in dedicated validation studies and are continuously assessed in the routine monitoring. We introduce also the quality indicators (uncertainty estimates) provided along with the atmospheric profiles to support quality control and data acceptance on user side, accordingly to their applications.
Jana Campa compares IASI L2 and AMDAR profiles and provides an estimation on usability of CAPE derived from IASI L2 profiles.
Length: 33 minutes.
The knowledge of the vertical structure of the atmosphere is extremely important for a reliable weather forecast, especially in the case of severe convection. The arrival of the new infrared sounder with the MTG will open many new possibilities in assessing the atmospheric instability. However, satellite retrievals lack accuracy towards the lower levels, which are crucial fort the calculation of several stability indices.
In the first part of the talk, a comparison of stability indices calculated from IASI L2 and AMDAR aircraft profiles will be presented. The probability of detection can be relatively high with adapted thresholds, but unfortunately also false alarm ratios are relatively high. In the second part, the uncertainty of CAPE resulting from errors in the retrieved profiles will be estimated.
Zsofia Kocsis presents an investigation of blended IASI and Synop measurements in a convective environment.
Length: 44 minutes.
Using IASI L2 profiles, different instability indices (e.g. Lifted Index, CAPE) and water vapour content in different layers can be determined, which provides information on the convective environment. These indices were studied in several convective cases which led us to try to merge the IASI profiles and Synop measurements. In this presentation we present the reasons why we choose to combine these different measurements and we also present some of our experiences with the blended IASI product.
Christian Herold presents case studies in order to give an answer if IASI profiles help predicting sting jets.
Length: 37 minutes.
Strong winds southwest of the centre of a Shapiro-Keyser-Cyclone are often associated with a cold conveyor jet or a sting jet. The sting jet is a strong mesoscale flow with a very high damage potential. It is a huge challenge for NWP and forecasters to predict correctly a sting jet. The question is: Can IASI profiles help us for a better prediction of such mesoscale severe wind events connected with sting jets? Therefore, some case studies will be presented.
Presentation 8 in the Warnings Event Week 2017
Length: 31 min
Author: Daniel Murer (MeteoSwiss)
Severe weather warnings at MeteoSwiss started more than thirty years ago, firstly with warnings for heavy precipitation. After the storm 'Lothar' in 2001 warnings for wind, rain and snow have been introduced and then the system was updated in 2009 with new software, NinJo. After this short introduction, Daniel Murer from MeteoSwiss will present us a case that will illustrate the process of issuing warnings and decision making in the Swiss Met Service.
Presentation 3 in the Marine Forecasting Course 2017
Length: 112 min
Author: Rasmus Tonboe (DMI)
Sea ice has always posed a threat to ships sailing through the northern Atlantic and also the ice was a clear indication of climate changes since the start of satellite observations in the 1970s. Satellites from their beginning have helped very much in tracking the condition and movements of ice sheets over North Pole and Antarctica. Sea ice condition, its melting and freezing over again in winter are important to track to see how they are affecting the weather and climate in these parts. Many satellite products and models were developed to distinguish thin one year ice from the thicker multiyear ice and to determine the actual thickness of these sheets. Further questions like how does ice affect radiation, how does snow affect the ice and what is the quality of the models that are used, will be answered during this lecture.