Overview

Project Highlights:

  • Analysis of first ever observations of weather events from CubeSat passive microwave radiometers
  • Use of CubeSats for understanding atmospheric processes
  • Collaboration with satellite company in order to produce high-fidelity weather information products

 

Overview

Recent scientific and operational applications in different fields (e.g. meteorology, hydrology, agriculture) have introduced the need for higher space-time monitoring of the Earth’s atmosphere and surface. Increased space-time resolution also is a need for clouds and precipitation observations for meteorology , due to their very rapidly evolving structure. Such need cannot be met by the current constellation of environmental and meteorological satellites due to their low revisit time and high cost. Novel strategies thus become necessary to ensure cost effective and higher space-time resolution earth-observation initiatives trying to break the traditional trade-off in EO mission design between geostationary and low-Earth orbiting missions. Orbital Micro Systems (OMS) is a world-leader in developing advanced instrumentation for small satellites focused at gathering weather data. Weather events in their most extreme forms (e.g. hurricanes, flash-floods and heatwaves) have shown that unpreparedness threatens the safety of millions every day. New observing systems are urgently needed.

Ground-breaking engineering techniques developed by OMS in recent years have made possible to build passive microwave radiometers of the size of a shoebox. The consequent reduction in sizes and costs paves the way towards the exploitation of satellite constellations that can monitor weather with unprecedented time resolution. A technology demonstrator with a payload consisting of a 10 x 10 x 15cm-sized instrument in a 3U CubeSat satellite, will be launched in 2019 as part of the In-Orbit Demonstration (IOD) Programme, funded by Innovate-UK and managed by the Catapult. OMS is planning to launch a full constellation of 50 Global Environmental Monitoring Satellites (GEMS) by 2022, each with a payload of a passive microwave radiometer capable of recording temperature, humidity and precipitation profiles throughout the atmosphere. When the full constellation will be operational, OMS will be able to provide global coverage at 16km2 resolution, with data refreshed every 15 minutes, rather than once or twice per day, which is currently the norm. This capability will pave the way towards more accurate forecasting enabling faster, informed decision-making in presence of weather-driven emergencies and to a vast gamut of opportunities in various markets ranging from aerospace and maritime transportation to extreme weather monitoring.

Figure 1. Brightness temperatures sensed by a passive microwave radiometer with red cores highlighting regions of deep convection and potential hotspots for severe weather phenomena.

Methodology

In order to properly use the anticipated OMS constellation of passive microwave radiometers the sensor brightness temperatures must be properly validated. It is therefore paramount to develop validation techniques and quantify retrieval uncertainties. First a prescreening process to identify and remove calibration biases that occur along the orbit path (e.g. ascending versus descending calibration differences, and seasonal calibration changes) will be implemented. Validation of the eight GEMS sounding channels around the 118.7503 GHz O2 line will be performed by utilizing radiosonde-based clear-sky temperature and humidity profiles (e.g. those extracted over U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) sites, Berg et al., 2015). The observed profiles are used as input to a radiative transfer model to calculate single differences (i.e., observed minus simulated brightness temperatures) for bias correction identification based on overpasses of those sites. Cross-overs of other operational satellites can be further used to validate the GEMS-IOD radiometer.

Training and Skills

This project offers an excellent opportunity to develop and apply novel microwave techniques to remote sensing of clouds and precipitation. The student will be trained in a wide range of topics including radiative transfer and cloud & precipitation remote sensing. Applicants should have a science or engineering degree. Knowledge of meteorology would be beneficial. Programming skills in matlab/idl/Python/C/Java/C++ and knowledge of signal propagation and numerical modelling would also be beneficial.

Timeline

Year 1: The student will become familiar with microwave radiative transfer and will apply radiative transfer codes to radiosonde profiles. Different sites will be selected as part of comprehensive validation campaign. Radiative transfer models will be developed during this period.

Year 2: Calibrated GEMS satellite data will be identified for co-located antenna temperature validation. A match-up procedure for time- and space coincidence matching will be developed.

Year 3: An operational validation procedure will be developed to provide continuous validation of GEMS satellites. Clear air regions will be identified and differentiated from cloudy and precipitating regions (e.g. heavy clouds, stratiform, and deep convection-- see Fig.1).

Partners and collaboration (including CASE)

A close collaboration between the Leicester Earth Observation Science group and OMS science team is at the core of this project. The collaboration with the Satellite Catapult will facilitate the development of weather products from the future constellation of GEMS satellites.

 

Further Details

Dr Battaglia is a cloud and precipitation microwave remote sensing expert with more than 18 years of experience in the field, member of the NASA Global Precipitation Measuring mission Science team and Member of the ESA-JAXA Mission Advisory Board. He is based in the Earth Observation Science Group within the Department of Physics (https://www2.le.ac.uk/departments/physics/research/eos/dr.-alessandro-battaglia). He is also member of NCEO (www.nceo.ac.uk).

Albin J. Gasiewski is Professor of Electrical and Computer Engineering at University of Colorado, Director of the CU Center for Environmental Technology, and Chief Scientist of OMS. He has 35 years experience in developing passive microwave remote sensing sensors, systems, and algorithms, for weather forecasting.

Prof. H. Boesch is the head of the Earth Observation Science Group and an expert in satellite instrumentation and remote sensing.