The day started as most days do in the last few months, wake up, think about thesis, get up, have breakfast thinking about thesis. Sit at desk, and work on thesis... then dad called me to help him with his windows reinstallation as there were some things not working properly....hmmmm....easy....
It was a 3 partition drive (1. for the OS; 2. for data; 3. for more data). Dad wanted me to wipe the first partition, do whatever it took to get the sound card working....
Anyway, so this is were the story gets long because I misunderstood, and thought I had complete reign of the whole computer....so I, deleted all partitions:
1. Formatted from an ntfs (a 3 partition drive) to linux and installed fedora (to check if the hardware was okay under a different OS - it was)
2. Formatted the linux single partition into 3 sections, and installed windows....
Then, realised (with dad's help and shock/horror expression) that there was precious data on partition 2 and 3 of the original drive....
OH MY GOODNESS! I can't even begin to re-live the sinking feeling and cold sweat you succumb to when you realise you deleted someone else's data (I wouldn't have felt so bad about my data - I have had a few experiences of this myself, and it doesn't feel nearly as bad).
Anyway, after two days of agony and pouring over the internet, learning about NTFS/ext3 and keeping positive (the thought that the military shoots holes through their drives to completely render their data deleted)....it's over, everything is safe and sound, and I am expert at hdd recovery! :) I even managed to recover the mounting point (and mount it) for the third partition!
The software that saved the day and that I highly recommend (after trying at least three others) is: Active@ UNDELETE 7 Professional. It is simple, elegant and best of all works! It's embarrassingly easy to use, and basically all that I learned in the two days of 'recovery mode' I didn't need if I had found that software right at the start.
Sunday, February 21, 2010
Thursday, February 11, 2010
Climate Change
Some time back, we would be talking of ‘global warming’, a scientific hypothesis that human induced carbon emissions are substantial enough to alter the climate and weather patterns of our planet. These days we talk
of ‘climate change’, and this expression not only more accurately describes the climatic events (which are no longer just ‘warming’) that have been observed and are being predicted but most importantly gives credence to the fact that this is becoming a ‘phenomenon’ of sorts. Climate change is no longer just affecting our climate system, but through peoples efforts it is having an effect on our thinking, society, our markets, policy, economics, and industry. Sadly constantly the phrase rings out – I ‘believe’ in climate change, I do not ‘believe’ in climate change.
I hope we are all here because we do not believe in climate change, but because as we see its far reaching influence, we want to ‘know’ more about it.
of ‘climate change’, and this expression not only more accurately describes the climatic events (which are no longer just ‘warming’) that have been observed and are being predicted but most importantly gives credence to the fact that this is becoming a ‘phenomenon’ of sorts. Climate change is no longer just affecting our climate system, but through peoples efforts it is having an effect on our thinking, society, our markets, policy, economics, and industry. Sadly constantly the phrase rings out – I ‘believe’ in climate change, I do not ‘believe’ in climate change.
I hope we are all here because we do not believe in climate change, but because as we see its far reaching influence, we want to ‘know’ more about it.
Wednesday, February 10, 2010
My thesis abstract!
Finally, the latest draft of my abstract is ready, hope it makes sense :)
I really cannot wait to submit!
-----------------------------------
Antarctic sea ice and its snow cover are integral components of the global climate system, yet many aspects of their vertical dimensions are poorly understood, making their representation in global climate models poor. Remote sensing is the key to monitoring the dynamic nature of sea ice and its snow cover. Reliable and accurate snow thickness data from an airborne platform is currently a highly sought after data product. Remotely sensed snow thickness measurements can provide an indication of precipitation levels. These are predicted to increase with effects of climate change, and are difficult to measure as snow fall is frequently lost to wind-blown redistribution,
sublimation and snow-ice formation. Additionally, accurate regional scale snow thickness data will increase the accuracy of sea ice thickness retrieval from satellite altimeter freeboard estimates.
Airborne snow depth investigation techniques are one method, providing a means for regional estimation of these parameters. The airborne datasets are better suited to validating satellite algorithms, and are themselves easier to validate with in-situ measurement. The development and practicality of measuring snow thickness over sea ice in Antarctica using a helicopter borne radar forms the subject of this thesis. The radar design, 2 - 8 GHz Frequency Modulated Continuous Wave Radar, is a product of collaboration and the expertise at the Centre for Remote Sensing of Ice Sheets, Kansas University.
This thesis presents a review of the theoretical basis of the interactions of electromagnetic waves with the snow and sea ice media. The dominant general physical parameters pertinent to electromagnetic sensing are presented, and the necessary conditions for unambiguous identification of the air/snow and snow/ice layers for the radar are derived. It is found that the roughness of the snow and ice surfaces are a dominant determinant in the effectiveness of layer
identification in this radar. Motivated by these results, the minimum sensitivity requirements for the radar are presented.
Experiments with the radar mounted on a sled confirm that the radar is capable of unambiguously detecting snow thickness. Helicopter borne experiments conducted during two voyages into the East Antarctic sea-ice zone show however, that the airborne data are highly affected by sweep frequency non-linearities, making identification of layering difficult. A model for the source of these non-linearities in the radar is developed and verified, motivating the derivation of an error correcting algorithm. Application of the algorithm to the airborne data set demonstrates that the radar is indeed receiving reflections from the air/snow and snow/ice interfaces.
Consequently, this thesis presents the first in-situ validated snow thickness estimates over sea ice in Antarctica derived from a Frequency Modulated Continuous Wave radar on a helicopter-borne platform. Additionally the ability of the radar to independently identify the air/snow and snow/ice layers allows for a relative estimate of roughness of the sea ice to be derived; this parameter
is a critical component necessary for assessing the integrity of satellite snow thickness retrieval algorithms such as those using the AMSR-E data product.
This thesis provides a description and solution or mitigation of the many difficulties of operating a radar from a helicopter-borne platform, as well as tackling the difficulties presented in study of heterogeneous mediums such as sea ice and its snow cover. In the future the accuracy of the snow depth retrieval results can be increased as technical difficulties are overcome, and at the same time the radar architecture can be simplified. However, further validation studies are suggested to better understand the effect of the heterogeneous nature of sea ice and its snow cover on the radar signature.
I really cannot wait to submit!
-----------------------------------
Antarctic sea ice and its snow cover are integral components of the global climate system, yet many aspects of their vertical dimensions are poorly understood, making their representation in global climate models poor. Remote sensing is the key to monitoring the dynamic nature of sea ice and its snow cover. Reliable and accurate snow thickness data from an airborne platform is currently a highly sought after data product. Remotely sensed snow thickness measurements can provide an indication of precipitation levels. These are predicted to increase with effects of climate change, and are difficult to measure as snow fall is frequently lost to wind-blown redistribution,
sublimation and snow-ice formation. Additionally, accurate regional scale snow thickness data will increase the accuracy of sea ice thickness retrieval from satellite altimeter freeboard estimates.
Airborne snow depth investigation techniques are one method, providing a means for regional estimation of these parameters. The airborne datasets are better suited to validating satellite algorithms, and are themselves easier to validate with in-situ measurement. The development and practicality of measuring snow thickness over sea ice in Antarctica using a helicopter borne radar forms the subject of this thesis. The radar design, 2 - 8 GHz Frequency Modulated Continuous Wave Radar, is a product of collaboration and the expertise at the Centre for Remote Sensing of Ice Sheets, Kansas University.
This thesis presents a review of the theoretical basis of the interactions of electromagnetic waves with the snow and sea ice media. The dominant general physical parameters pertinent to electromagnetic sensing are presented, and the necessary conditions for unambiguous identification of the air/snow and snow/ice layers for the radar are derived. It is found that the roughness of the snow and ice surfaces are a dominant determinant in the effectiveness of layer
identification in this radar. Motivated by these results, the minimum sensitivity requirements for the radar are presented.
Experiments with the radar mounted on a sled confirm that the radar is capable of unambiguously detecting snow thickness. Helicopter borne experiments conducted during two voyages into the East Antarctic sea-ice zone show however, that the airborne data are highly affected by sweep frequency non-linearities, making identification of layering difficult. A model for the source of these non-linearities in the radar is developed and verified, motivating the derivation of an error correcting algorithm. Application of the algorithm to the airborne data set demonstrates that the radar is indeed receiving reflections from the air/snow and snow/ice interfaces.
Consequently, this thesis presents the first in-situ validated snow thickness estimates over sea ice in Antarctica derived from a Frequency Modulated Continuous Wave radar on a helicopter-borne platform. Additionally the ability of the radar to independently identify the air/snow and snow/ice layers allows for a relative estimate of roughness of the sea ice to be derived; this parameter
is a critical component necessary for assessing the integrity of satellite snow thickness retrieval algorithms such as those using the AMSR-E data product.
This thesis provides a description and solution or mitigation of the many difficulties of operating a radar from a helicopter-borne platform, as well as tackling the difficulties presented in study of heterogeneous mediums such as sea ice and its snow cover. In the future the accuracy of the snow depth retrieval results can be increased as technical difficulties are overcome, and at the same time the radar architecture can be simplified. However, further validation studies are suggested to better understand the effect of the heterogeneous nature of sea ice and its snow cover on the radar signature.
Thursday, February 4, 2010
Oliver Heaviside
I have known Oliver Heaviside's work, and a little of his life for a long time of course, but today I am particularly full of admiration. Here is a photograph of him (from wiki... duh :D)
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