Meteorological and climatological conditions affecting the vertical structure of visibility in Northern Germany Final technical report

Supported by: European Research Office, London (GB)SIGLETIB: AC 8534 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Ein eindimensionales Energie-Massenbilanzmodell einer Schneedecke unter Beruecksichtigung der Fluessigwassertransmission

Copy held by UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Messungen von Oberflaechentemperaturen als Teil der Energiebilanz unter Beruecksichtigung von im Anfangsstadium geschaedigten gartenbaulichen Kulturen als Beitrag zur moeglichen Energieeinsparung bzw. Verringerung des Aufwands an Pflanzenschutzmittel Abschliessender Sachbericht

TIB Hannover: D.Dt.F. AC 1000(36,46) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Simulation mesoklimatischer Strukturen in urbanen Ballungsraeumen unter Vorgabe regionaler Klimaaenderungen Abschlussbericht

Within this project, a relatively simple method was used to regionalize both the influences of global climate changes as well as the influences of changes in urban built-up area structures for the city of Berlin. These investigations were conducted using the FITNAH mesoscale model, while the simulation results from the ECHAM-1 global climate model of the Max-Planck-Institute were used as large-area input data. Information covering large areas on climatologically representative days were obtained by means of a three-dimensional FITNAH version which was extended by cloud and precipitation physics in the course of the project, in order to permit taking into account the water resources of the city. Information concerning the annual variation of boundary-layer specific variables, e.g. the frequencies of inversions relevant to the propagation of emissions, were obtained by means of a one-dimensional FITNAH version especially conceived for long-term simulation. Here particular attention had to be given to the parameterization of soil humidity as this has a strong influence on the history of surface meteorological variables through latent heat. (orig./HM)Innerhalb dieses Projektes wurden mit einem relativ einfachen Verfahren zur Regionalisierung die Einfluesse globaler Klimaaenderungen, sowie die Einfluesse von Aenderungen in staedtischen Bebauungsstrukturen fuer die Stadt Berlin untersucht. Diese Untersuchungen wurden mit Hilfe des Mesoscale Modelles FITNAH durchgefuehrt, wobei als grossraeumige Eingabedaten die Simulationsergebnisse des globalen Klimamodelles ECHAM-1 des Max-Planck-Institutes benutzt wurden. Flaechendeckende Informationen klimatologisch repraesentativer Tage wurden dabei mit Hilfe einer dreidimensionalen Version von FITNAH gewonnen. Diese Version wurde im Laufe des Projektes um Wolken- und Niederschlagsphysik erweitert, um den Wasserhaushalt der Stadt beruecksichtigen zu koennen. Informationen ueber den Jahresgang grenzschichtspezifischer Variablen, wie z.B. die fuer die Schadstoffausbreitung relevanten Inversionshaeufigkeiten, wurden mit Hilfe einer speziell fuer Langzeitsimulationen konzipierten eindimensionalen Version von FITNAH erhalten. Hier musste besonderes Augenmerk auf die Parameterisierung der Bodenfeuchte gerichtet werden, da diese den Verlauf der bodennahen meteorologischen Variablen durch die latente Waerme stark beeinflussen. (orig./HM)SIGLEAvailable from TIB Hannover: F94B911+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Entwicklung von Parametrisierungsansaetzen fuer globale Modelle zur Verdunstung von heterogenen Pflanzenbestaenden unter Beruecksichtigung mesoskaliger Reliefformen Schlussbericht

The interactions between the atmosphere and land- and sea surfaces are of great influence on the state of local climate. To run GCM's successfully, the understanding of e.g. the evaporation and transpiration of land surfaces and vegetation is a very important aspect. The often heterogeneous terrain turns out to be a problem when mean-values of latent heat fluxes over certain considerable large areas have to be estimated. Therefore, the aim of the project was an enlargement of understanding, an estimation of the order of magnitude with which the influence of heterogeneous structures could be described and a efficient parameterization of those heterogenous structures. The mesoscale model FITNAH was successfully applicated to simulate both, the explicitly resolved terrain with the 3D-version and the 1D-runs with the parameterization approach. Based on the Penman-Monteith-scheme and by using a Darcy-type soil-water-budget-model the scheme is able to consider 10 different kinds of vegetation and 11 types of soil. The results with the newly developed approach turned out to be more realistic than formerly implemented parameterizations. The latent heat flux varies in the order of magnitude of 5% when the surface is flat, but heterogeneously overgrowed with. A more accentuated difference occurs, when structures with a considerable influence on the wind field are involved: with large forests and urban zones, the deviation reaches values of 15%, and when complex terrain is present in combination with thermally induced wind systems, a difference up to 25% can be detected. The comparison with experimental data sets lead to the understanding, that the newly implemented approach is quite successful as long as flat terrain can be presumed, so that the use in GCM's can be recommended. When it comes to wind-field-modifying structures, further research has to be done to complete the parameterization scheme. (orig.)SIGLEAvailable from TIB Hannover: F98B1654+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Das Landoberflaechen-Klimaprogramm Abschlussbericht

In the course of LOTREX-10E (longitudinal land-surface traverse experiment 10 E) several experiments along 10 East were planned in order to obtain sets of climate related surface paramters at different latitudes. The results should be representative for areas in the scale of satellite-pixels or the grid-scale of climate models, respectively. One intention was the validation of satellite data for climate observation, another one the check and correction of actual climate models. For this purpose two interdisciplinary field experiments HIBE'88 and HIBE'89 (Hildesheimer Boerde Experiment) were conducted 1988 and 1989 in Northern Germany near Hannover. In the second part of this paper the principal objective of the experiments and the aims of the participants are presented. (orig.)Im Rahmen von LOTREX-10E (Land-Oberflaechen-Traversen-Experiment 10 E) sollten verschiedene Experimente entlang des zehnten oestlichen Laengengrades durchgefuehrt werden mit dem Ziel, vollstaendige Datensaetze der klimarelevanten Oberflaechenparameter fuer verschiedene geographische Breiten zu erhalten. Diese Ergebnisse sollen repraesentativ fuer Flaechen sein, die in der Groessenordnung von Satellitenpixeln bzw. der Maschenweite von Klimamodellen liegen. Ziel ist einerseits die Validierung von Satellitenmessungen, um sie zur Klimabeobachtung einzusetzen, andererseits die Ueberpruefung und Verbesserung der bestehenden Klimamodelle. Mit dieser Zielsetzung wurden 1988 und 1989 in Norddeutschland die beiden interdisziplinaeren Experimente HIBE'88 und HIBE'89 (Hildesheimer Boerde Experiment) durchgefuehrt. Im zweiten Teil dieses Berichtes soll die Fragestellung und die experimentelle Ausstattung der teilnehmenden Institute kurz dargestellt werden. (orig.)SIGLEAvailable from TIB Hannover: F95B449+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

HELIPOD. Ein hubschraubergestuetztes meteorologisches Messsystem Abschlussbericht

In order to provide reliable future prognosis by means of numerical climate models the present knowledge of the energy flows at the earth surface must still be improved by another magnitude with respect to measuring exactness. In order to solve the related problems in the field of measuring technique, the helicopter-supported meteorological turbulence measuring system HELIPOD has been developed world-wide for the first time in the frame of the project that is described in this article. It enables the necessary in-situ process studies especially in regions which are difficult to reach in terms of logistics. The manifold aspects of the project are described in the final report: planning of the project, preconditions, preliminary works, co-operation with other institutions, desires and demands on HELIPOD, advantages and special characteristics of the new system, course of the project, construction, erection and quality controls, partial solutions and technical properties of the measuring system HELIPOD and finally experience gained during construction, test phase and first operational applications on a ship in the Arctic. The appendix does not only contain an extensive bibliography but also various original documents as well as press commentaries. (KW)SIGLEAvailable from TIB Hannover: F96B358+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Regionalisierung von Niederschlag und Verdunstung zur besseren Parametrisierung des hydrologischen Zyklus in Klimamodellen Schlussbericht

In climate models the characterization of the hydrological cycle poses a problem. Coarse resolution of models (#propor to# 300 km) results in underrating of precipitation intensity because the analysed time and area related values are average values. As a consequence, interception loss is overrated (Doman/Gregory, 1992) because information regarding the distribution of precipitation in a given area is inadequate. Since these two quantities, being part of the water cycle, bear on conditions at ground level including evaporation and runoff, the description of the latter quantity is bound to be fraught with error. (orig.)In Klimamodellen stellt die Beschreibung des hydrologischen Zyklus ein Problem dar. Die grobe Aufloesung der Modelle (#propor to#300 km) fuehrt durch die Betrachtung von Mittelwerten ueber Zeit und Raum zu einer Unterschaetzung der Niederschlagsintensitaet. Eine Folge dieser Unterschaetzung ist aufgrund fehlender Informationen ueber die Verteilung des Niederschlags innerhalb der betrachteten Flaeche die Ueberbewertung des Interzeptionsverlustes (Dolman/Gregory, 1992). Da diese beiden Groessen als Teil des Wasserkreislaufs die Bedingungen am Erdboden einschliesslich Verdunstung und Abfluss beeinflussen, wird die Beschreibung der letztgenannten Groessen zwangslaeufig fehlerbehaftet sein. (orig.)SIGLEAvailable from TIB Hannover: F98B1899+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Auswertung der IHD-Messungen 1965-1974 Hannover-Herrenhausen Abschlussbericht

SIGLETIB Hannover: FR 1641+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Hochaufloesende Messungen turbulenter Energiefluesse in der planetaren Grenzschicht mit der hubschraubergestuetzten Schleppsonde HELIPOD Schlussbericht

This final report presents the results of the first meteorological field campaign in the nocturnal boundary layer over land with the recently developed measurement system HELIPOD. During the examination of HELIPOD's measurement characteristics and the determination of the turbulent energy fluxes after appropriate high pass filtering of the measured time series no systematic error in the turbulent fluxes could be found. The measurements in the nocturnal residual layer showed that HELIPOD detects the turbulent fluxes of momentum, sensible and latent heat without any measurable displacement from zero. In the strongly stably stratified ground inversion sensible heat fluxes of 0.1 Wm"-"2 and momentum fluxes less than 10"-"3 Nm"-"2 were detected from HELIPOD data. The turbulent flow in the ground inversion was in 100 m height strongly intermittent in general and decoupled from the surface roughness. Its turbulence production subrange was located at wavelengths of only a few meters. The local scales of this flow were in good agreement with results from other field experiments. A spectral analysis of nearly continuous turbulence found only on one flight leg showed spectral gaps in the power spectra of the wind velocity components at wavelengths between 2 and 10 m. An interaction with gravity waves could be excluded. The corresponding wavenumbers k of the gaps were in good agreement with the wavenumber k_* calculated by a model of Weinstock (1980). In accordance with the theory two-dimensional turbulence changes at k_* to three-dimensional turbulence with the inertial subrange. A transition from a k"-"5"/"3 to a k"-"3-law in the temperature spectra could be explained by the decay of turbulence on small scale due to the strong stratification. The observation of decaying turbulence and spectral gaps at wavelengths less than 10 m was owing due to the highly resolving sensor equipment of the HELIPOD. (orig.)SIGLEAvailable from TIB Hannover: F98B1651+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman