EESS talk on "Measuring snowfall in Antarctica: the APRES3 project"
Event details
| Date | 07.06.2016 |
| Hour | 12:15 › 13:15 |
| Speaker | Dr Jacopo Grazioli, LTE |
| Location | |
| Category | Conferences - Seminars |
Abstract:
Antarctica is an inhospitable continent. The only possible in-situ measurement networks are those for which robust methods and sensors exist that can run in fully automatic mode, unattended over long periods of time, and exposed to harsh conditions. This is not the case for the measurement of precipitation. The measurement of snowfall is notoriously difficult in general, and difficulties are exacerbated in Antarctica. On the high Antarctic plateau, where less than 20 mm of equivalent water are thought to accumulate each year, frost deposition and extreme cold temperature adversely affect traditional precipitation gauges. At the coastal regions, catabatic winds induce frequent blowing snow which blur snowfall observation. A lack of validation data may be a reason why climate models (used to predict climate trends) considerably diverge. The models all predict that antarctic precipitation will increase in a warming climate and unsurprisingly they diverge as to the magnitude of the increase. There is thus a strong need for a model-free (i.e. not based on meteorological analyses or re-analyses) dataset of antarctic precipitation to evaluate and validate the models.
The APRES3 (Antarctic Precipitation: REmote Sensing from Surface and Space) campaign was recently launched and a first field experiment took place from November 2015 until February 2016. Instruments dedicated to the observation of solid precipitation have been deployed at the French Antarctic station Dumont d'Urville on the coast of Adélie Land in Antarctica. On the remote sensing side, a depolarization lidar and two weather radars were nearly collocated. For measurement at the ground level, a weighing gauge (with wind shield) and a multi-angle snowflake camera (MASC) were complementing the remote sensing instruments. In addition, daily radiosounding records collected by MeteoFrance were available. The measurements collected by these instruments cover many aspects of precipitation, never measured before in this location: from the vertical development of snow-generating clouds and their large scale (km) features, until the accumulation of snow at the ground level and the shape, size, type of individual ice crystals and snowflakes.
This experimental set up is a first step towards understanding Antarctic precipitation at its different scales, as well as to evaluate the added value of remote sensing instruments to monitor snowfall in this environment.
Short biography:
Jacopo Grazioli is a postdoctoral researcher at the Environmental Remote Sensing (LTE) laboratory at EPFL. He holds Bachelor and Master degrees in Environmental Engineering from the University of Padua, Italy and a PhD obtained at LTE in July 2015. After an experience as scientific expert for Meteo Swiss, he currently conducts his post-doc at EPFL within the framework of the APRES3 campaign, aiming at measuring precipitation on the Antarctic continent.
Antarctica is an inhospitable continent. The only possible in-situ measurement networks are those for which robust methods and sensors exist that can run in fully automatic mode, unattended over long periods of time, and exposed to harsh conditions. This is not the case for the measurement of precipitation. The measurement of snowfall is notoriously difficult in general, and difficulties are exacerbated in Antarctica. On the high Antarctic plateau, where less than 20 mm of equivalent water are thought to accumulate each year, frost deposition and extreme cold temperature adversely affect traditional precipitation gauges. At the coastal regions, catabatic winds induce frequent blowing snow which blur snowfall observation. A lack of validation data may be a reason why climate models (used to predict climate trends) considerably diverge. The models all predict that antarctic precipitation will increase in a warming climate and unsurprisingly they diverge as to the magnitude of the increase. There is thus a strong need for a model-free (i.e. not based on meteorological analyses or re-analyses) dataset of antarctic precipitation to evaluate and validate the models.
The APRES3 (Antarctic Precipitation: REmote Sensing from Surface and Space) campaign was recently launched and a first field experiment took place from November 2015 until February 2016. Instruments dedicated to the observation of solid precipitation have been deployed at the French Antarctic station Dumont d'Urville on the coast of Adélie Land in Antarctica. On the remote sensing side, a depolarization lidar and two weather radars were nearly collocated. For measurement at the ground level, a weighing gauge (with wind shield) and a multi-angle snowflake camera (MASC) were complementing the remote sensing instruments. In addition, daily radiosounding records collected by MeteoFrance were available. The measurements collected by these instruments cover many aspects of precipitation, never measured before in this location: from the vertical development of snow-generating clouds and their large scale (km) features, until the accumulation of snow at the ground level and the shape, size, type of individual ice crystals and snowflakes.
This experimental set up is a first step towards understanding Antarctic precipitation at its different scales, as well as to evaluate the added value of remote sensing instruments to monitor snowfall in this environment.
Short biography:
Jacopo Grazioli is a postdoctoral researcher at the Environmental Remote Sensing (LTE) laboratory at EPFL. He holds Bachelor and Master degrees in Environmental Engineering from the University of Padua, Italy and a PhD obtained at LTE in July 2015. After an experience as scientific expert for Meteo Swiss, he currently conducts his post-doc at EPFL within the framework of the APRES3 campaign, aiming at measuring precipitation on the Antarctic continent.
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. Alexis Berne, LTE