Herman Russchenberg
medewerkers 165 (3271K)  

Prof.dr.ir.Herman Russchenberg

 Chair Remote Sensing of the Environment
 Delft University of Technology
 

atmospheric remote sensing
e-mail address

I am fascinated by the observation-and-interpretation process. Most observations we do - whether scientific or social- are indirect: one never measures the meaning directly, but needs assumptions and models before the interpretation can be made. This is also true for remote sensing. The direct measurement is often expressed in terms of energy or power, but what one wants to know is: how much rain is falling?, or how do aerosols change clouds? This requires a good understanding of the underlying physics, the observation technology and of signal processing. It truly needs a multi-disciplinary approach.

Science and education go hand in hand. Teaching sharpens the scientist's mind, and at the same time educates students within the practice of scientific enterprise. To a large extent science and technology are autonomous enterprises, but the actors- scientists and engineers- share a special responsibility: they should serve mankind. Technical and exact sciences are in many respects the motors that drive the modern society and high quality educational programs are crucial for maintaining the high standard of living, today and in the future. Educational programs should reflect the interaction between science and technology on the one hand, and societal needs on the others. An educational program should put content in context:
  • it has to unveil the societal relevance of technology;
  • it has to be open to new developments in the society;
  • it has to challenge the students to think beyond the boundaries of their scientific disciplines;
  • it has to make the students enthusiastic and proud.

  • Professional interests
  • Climate change: the role of clouds and aerosols in the climate system
  • Remote sensing of the atmosphere
  • Forecasting society-disruptive weather
  • Education in relation to research

  • Why is the climate changing?
    The best understood source for global warming is the increasing level of greenhouse gases in the atmosphere. The least understood factor is the effect of aerosols and clouds. Aerosols are fine dust particles in the atmosphere that serve as catalysers formation of water droplets. An increase of the aerosol concentration, by human activities for instance, leads to a larger number of cloud particles and longer cloud lifetime; the resulting cloud reflects more solar radiation. This may cool the atmosphere in contrast to greenhouse warming. However, the clouds will also respond to global warming. Cloud decks might open up so that more solar radiation reaches the surface to warm it. It is largely unknown what clouds will do in a changing climate: will they counteract global warming, or reinforce it?

    How can we measure clouds?
    It is difficult to measure physical properties of clouds. Not only do they drift at large heights, but also the cloud droplets are very small - in the order of 10 micrometer. The only way is remote sensing. Radars, lidars and radiometers are the key instruments. A radar and lidar transmit an electromagnetic signal towards the clouds and measure the reflections. A radar operates at a wavelength between 3 mm and 20 cm, whereas a lidar uses a laser beam as the source, usually in the infrared. A radiometer is a passive device, and only measures atmospheric radiation emanating from the atmosphere. But why do we need these different instruments? Is one instrument not enough? No. Sometimes the cloud droplets are too small to be seen by radar, and sometimes the clouds are too thick for lidar signals to penetrate to the cloud top. Only the combination of instruments - sensor synergy - will give a full picture. Central to our work is Cesar Observatory.

    Research activities
    Experimental remote sensing
  • Sensor synergy (radar, lidar, radiometry) to measure cloud properties relevant for climate studies
  • Radar retrieval of rainfall parameters: doppler-polarimetric and dual-frequency techniques.
  • Space-based retrieval of cloud parameters
  • Radar Doppler-polarimetry for atmospheric dynamics.
  • Radar Doppler-polarimetry for mixed-phase clouds studies.

  • Electromagnetic scattering
  • Coherent scattering of radar waves by clouds
  • Electro-magnetic scattering by the melting layer in precipitation.
  • Scattering by rain
  • Multiple scattering of lidar waves by water clouds.
  • The radar discrepancy: scattering by semi-discrete clouds.

  • Signal processing
  • Processing concepts for the TU Delft atmospheric radar systems
  • Doppler-polarimetric target enhancement
  • Clutter suppression

  • System studies and design
  • Radar calibration
  • Scientific user strategies of the transportable atmosphere radar TARA
  • Development of the IRCTR Drizzle radar IDRA

  • Educational activities
  • oral lectures;
  • working groups;
  • development of courses and course material;
  • laboratory exercises;
  • coordination of education activities;
  • organization of special events (excursions, student symposia, guest lectures);
  • quality control of the education program;
  • supervision of graduate students.

  • Leadership

    Science
    I am heading the atmospheric remote sensing group at TU Delft.  In this capacity I am supervising a research and technical team - with an average size of 10 persons - and am responsible for all managerial tasks related to it:

    ·  Project acquisition and management;

    ·  Quality assurance;

    ·  Recruitment of post-docs, PhD students and guest scientists;

    ·  Initiating and stimulating (inter)national cooperation;

    ·  Definition of the research program;

    ·  Communication with scientific partners and stakeholders.

    I am director of the TU Delft Climate Institute, involving all TU Departments that deal with understanding, mitigation and adaptation of climate change.

     

    Education
    From March 2013 to September 2014 I was Director of Education of the Department of Civil Engineering and Geosciences. The department hosts 1800 students; 140 staff members are involved in the education programs. I was responsible for the quality of all education programs the Department offers.

     

    From November 2007 to August 2011 I was Director of Education of the Department of Electrical Engineering, Mathematics en Computer Science. The department hosts 1700 students; 160 staff members are involved in the education programs. I was responsible for the quality of all education programs the Department offers.



    Full CV on request.