Oct. 25, 2016, 6:15 p.m.
I can deliver on-site training workshops on a range of topics both in academic and private settings. Topics of expertise include:
Oct. 1, 2016, 9:49 a.m.
This post is part 2 in a series. Part 1 is here.
Sept. 30, 2016, 2:23 p.m.
It may surprise a few people to learn that this cliché is more-or-less accurate when it comes to most modern research. More-often-than-not researchers expect us to take their results on faith.
Sept. 6, 2016, 9:06 p.m.
Raoul is a diligent and hard working PhD student: He immerses himself in his subject, and feels like there is so much to learn with so little time. He may often feel on the outside looking in, racked with doubt, wondering whether he could ever contribute something meaningful to his field. His supervisor has given him some old code, allegedly related to an unrecognisably early version of their PhD project, maybe in something like FORTRAN or Matlab. Raoul doesn't have time to stop and smell the roses, he has to get cracking to produce results, write papers, defend, and get on the fast-track to academic success! For him, his main priority is learning his subject, and generating a new contribution to his field.
Sept. 11, 2016, 9:17 a.m.
Regression testing, unit tests, Test driven development, automated testing, defensive programming. Despite years in research, these were not terms I had heard, not from my supervisors or peers, not at conferences, and certainly not in journals or other scientific forums. Yet after working for a few months in UCL's RITS Research Software Development team, a group that emphasises software development to improve Science, I have woken up to the reality that software developers have known for a long time:
June 10, 2016, 9:04 a.m.
It has been a while since my last post, and a lot has changed. My time at the Department of Geosciences in the University of Oslo as a postdoc research fellow sadly came to a close; it was hard to move on and leave behind my friends and Norwegian life. I have many great memories of Norway, and hope it won't be too long before I return. Perhaps that will even be my last postdoc and the end of my professionally active research career. After 3 postdoc contracts I would say that is a bitter-sweet thought, as there are many pros and many cons of being a postdoc-probably a mix which you won't find in any other job-but 6 years of that lifestyle may be my limit. (And it is certainly not a lifestyle that is particularly complimentary to married-life!)
Feb. 24, 2016, 1:55 p.m.
This story starts around 2012, when I received a request to review a paper on solar activity and the Indian Monsoon from the journal Advances in Space Research. I have reviewed many such papers (perhaps ~20) so this was nothing unusual. A quick read revealed some tortured data, abused statistics, and nonsense prose. All in all a fairly typical manuscript in its field. A version of it can be found at ArXiv. (To get some idea of why I say this is a typical paper, have a look at Barrie Pittocks 1978 piece "Solar Cycles and the Weather: Successful Experiments in Autosuggestion?", although it is, unfortunately, pay-walled.)
Sept. 11, 2016, 9:33 a.m.
Last November someone e-mailed me a strange request, they wanted to use a method from a paper I wrote in 2013. Shocking I know. I had included in the paper a link to some IDL code meant to reproduce the figures, of course, it was already broken. It had aged badly, inaccessible a full 2 years ahead of Jeff Rotheberg's prediction ("digital information lasts forever — or five years, whichever comes first"). After digging through my file system and recovering the old script I had the feeling that if the link not been broken it would probably not have been of much help. Needless to say, at the time I wrote the paper I thought the approach I took was great. I didn't know much about coding then, and I hadn't heard of version control either. Although, to be fair, no one in the field I was working in talked about these issues or showed much interest in code. In fact, asking to see peoples code was a good way to loose friends ("You don't trust me?" or "You want to steal my work?"). A few years on, and I now know enough to see that approach I took was not terribly helpful if the aim was to create reproducible science.
Nov. 10, 2015, 10:29 a.m.
Over the past 4 years, more than 80 scientists from 20 countries across Europe have come together, in an EU-funded COST project, called TOSCA. These scientists came from a whole range of different backgrounds, including Solar and Space Physicists, Climatologists and Atmospheric Scientists, and everyone in-between. Over that time, they produced much on the subject of natural climate forcing mechanisms, including many meetings, workshops, training schools, short-term research grants, original research studies, synthesis reports, special journal editions and outreach materials. But the crown jewel of the collaboration is their newly-launched book, titled 'Earth's climate response to a changing Sun'.
Nov. 6, 2015, 1:35 p.m.
I recently attended a one-day evaluation workshop for the PERCICLES Project as an invited reviewer. PERICLES (#periclesfp7) stands for Promoting and Enhancing Reuse of Information throughout the Content Lifecycle taking account of Evolving Semantics. The aim was to give feedback and suggestions on the projects progress and how they could meet their goals. The meeting was hosted at the Belgium Institute for Space Aeronomy, in Brussels, and it took place on 29th October, 2015.
Sept. 22, 2015, 8:44 a.m.
I have just returned from a research trip in Croatia (8--19th September), with my friend and long-time collaborator Dr. Jasa Calogovic. Every now-and-then Jasa and I manage to have some schedule overlap for a collaborative trip: This time, he kindly put my wife and I up the beautiful Hvar Observatory, which is built around (and inside of) a Napoleonic Fortress.
Aug. 12, 2015, 8:45 a.m.
Scientists as advocates. Should Scientists step outside of their archetypal roles as dispassionate investigators of the physical world, taking time away from asking questions of how things are, and instead offer opinions on how they think things should be? Is this a moral obligation? Or is it simply dangerous irresponsible territory beyond their purview? Should we just be good little investigators and know our place? Or in fact, are these the wrong questions to ask, devoid of the nuance and perhaps ironically implying that even needing to ask it begs only the answer, 'when you grow up'.
July 23, 2015, 4:16 p.m.
This post differs from my usual fare as it follows the format of an FAQ of sorts. For me, it is representative of a conversation I have had a number of times now. I have found that the points raised are usually asked of me by people of a right-leaning political persuasion with some background knowledge of climate. But first some brief back-story to explain how this came about...
June 15, 2015, 5:31 a.m.
Earlier this year some colleagues emailed around the latest paper claiming a strong causal relationship between the solar cycle and some Earth-bound phenomena, in this case the fertility and lifetime of people born during different phases of the solar cycle in Norway from historic records. Usually, such studies are cause for some mirth, and make for useful examples of common statistical problems, see for example the relationship between cosmic rays and car crashes, or heart attacks and the solar cycle. The study was carried out by a group of Norwegian researchers and published in the prestigious Proceedings of the Royal Society B, and could be considered to be a confirmation study as it notes that it is supported by earlier findings.
June 5, 2015, 8:12 a.m.
Helping at the Software Carpentry course, June 2--3rd Oslo run by Lex Nederbragt and Karin Lagesen, certainly gave me a lot to consider. The two-day course taught novice users Bash, Git, and Python (Jupyter Notebook). Three invaluable and complimentary tools which are the centre of my own work-flow. I was excited to see how people were introduced to these tools and the Software Carpentry teaching methods. The collaborative Git-based lesson materials are especially nice, and I can only hope this teaching model spreads far and wide. I certainty appreciated running through the course material, and in particular I don't remember seeing a clearer introduction to Git and Bash.
Portrait of Priest Salvador Bodi y Congros
Changes in measurement frequency due to sensor path accounts for a small regionally-averaged periodicity observed in the pollution data.
Photo credit ep_jhu.
We have explored how variability changes with the area and sample size considered, altering the detectability of a signal in composites accordingly.
Freely access the full article from the journal of SWSC journal
A large dust event in March 2003, typical of the kind that regularly impacts the Canary Islands.
You can access the article from the Quarterly Journal of the Royal Meteorological Society.
Low (red) and high (blue) level cloud cover seen by satellites show an (inverse) artificial relationship. Just one of the many issues that come to bear on a proposed cosmic ray cloud link.
You can freely access this article from the journal of SWSC.
I also wrote a post on this subject for a general audience, which you can find here, hosted on the Royal Geographical Societies Climate Change Research Group blog.
Numerous articles of interest have appeared related to this publication, such as this one at RealClimate.
The largest regular daily increases in cloud as viewed by satellite.
Access the article from JGRs website±.
Around 600 contrails in this "outbreak" event. Their formation conditions, and their properties are explored in this paper.
View this article on JGRs website.
Locally significant correlations (±0.8) between cloud cover from MODIS and ENSO.
View this article in the Journal of Climate.
Co-temporal variations in solar parameters make evaluating short-term solar–cloud links problematic. In this work, we went to great lengths to separate various solar parameters as much as possible, yet found no response in the available cloud data.
View the article in GRL.
Note: For those especially interested in composite analysis material, I suggest looking at the 2013 (SWSC) on this page. If you are after a more general solar–climate material, then try the 2012 SWSC paper instead. Enjoy!
Changes in the galactic cosmic ray (GCR) flux due to variations in solar activity may provide an indirect connection between the Sun's and the Earth's climates. Epoch superpositional (composite) analyses of high-magnitude GCR fluctuations, known as Forbush decrease (FD) events, have been widely used to test this hypothesis, with varied results. This work provides new information regarding the interpretation of this approach, suggesting that FD events do not isolate the impacts of GCR variations from those of solar irradiance changes. On average, irradiance changes of ~0.4 W m-2 outside the atmosphere occur around 2 days in advance of FD-associated GCR decreases. Using this 2 day gap to separate the effects of irradiance variations from GCR variations on cloud cover, we demonstrate small, but statistically significant, anomalous cloud changes occurring only over areas of the Antarctic plateau in association with the irradiance changes, which previous workers had attributed to GCR variations. Further analysis of the sample shows that these cloud anomalies occurred primarily during polar darkness, precluding the possibility of a causal link to a direct total solar irradiance effect. This work suggests that previous FD-based studies may have ineffectively isolated the impacts of GCR variations on the Earth's atmosphere.
View the paper in JGR.
We demonstrate evidence that past composite based studies centred around the onset of Forbush decrease (FD) events may have improperly isolated the maximal galactic cosmic ray (GCR) decrease associated with the FD events. After an adjustment of the composite to account for such shortcomings we find indications of anomalous cloud cover decreases (of around 3%) located in the upper levels of the troposphere at high southern latitudes. These cloud changes are detectable after latitudinal averaging, suggesting the possibility of a second order relationship between the rate of GCR flux and cloud cover in this region. The maximal cloud change is observed in advance of the maximal GCR decrease; this implies that if the observed cloud changes bear a causal relationship to the rate of GCR flux, then cloud properties may be sensitive to changes in GCR conditions rather than the maximal deviations themselves.
Access the article at JASTP.
The effect of the Galactic Cosmic Ray (GCR) flux on Earth's climate is highly uncertain. Using a novel sampling approach based around observing periods of significant cloud changes, a statistically robust relationship is identified between short-term GCR flux changes and the most rapid mid-latitude (60°–30° N/S) cloud decreases operating over daily timescales; this signal is verified in surface level air temperature (SLAT) reanalysis data. A General Circulation Model (GCM) experiment is used to test the causal relationship of the observed cloud changes to the detected SLAT anomalies. Results indicate that the anomalous cloud changes were responsible for producing the observed SLAT changes, implying that if there is a causal relationship between significant decreases in the rate of GCR flux (~0.79 GU, where GU denotes a change of 1% of the 11-year solar cycle amplitude in four days) and decreases in cloud cover (~1.9 CU, where CU denotes a change of 1% cloud cover in four days), an increase in SLAT (~0.05 KU, where KU denotes a temperature change of 1 K in four days) can be expected. The influence of GCRs is clearly distinguishable from changes in solar irradiance and the interplanetary magnetic field. However, the results of the GCM experiment are found to be somewhat limited by the ability of the model to successfully reproduce observed cloud cover. These results provide perhaps the most compelling evidence presented thus far of a GCR-climate relationship. From this analysis we conclude that a GCR-climate relationship is governed by both short-term GCR changes and internal atmospheric precursor conditions.
Access the article at ACP.
Svensmark et al. (2009) have recently claimed that strong galactic cosmic ray (GCR) decreases during ‘Forbush Decrease (FD) events’ are followed by decreases in both the global liquid water cloud fraction (LCF) and other closely correlated atmospheric parameters. To test the validity of these findings we have concentrated on just one property, the MODIS LCF and examined two aspects: 1) The statistical chance that the decrease observed in the LCF is abnormal. 2) The likelihood of the observed delay (~5 to 9 days) being physically connected to the FD events. On both counts we conclude that LCF variations are unrelated to FD events: Both the pattern and timing of observed LCF changes are irreconcilable with current theoretical pathways. Additionally, a zonal analysis of LCF variations also offers no support to the claimed relationship, as the observed anomaly is not found to vary latitudinally in conjunction with cosmic ray intensity.
Access the article at GRL.
We examine thirty years of atmospheric extinction obtained from both stellar and solar telescope measurements, at ~ 2.4km above sea level, from the North Atlantic Canary Archipelago—an island chain located at approximately 28°N, around 100 km from the west coast of Africa. We also use data from three AERONET monitors, located at varying heights on one of the main islands, although these are only available over a shorter (<10 yr) period. The Canary Archipelago is regularly affected by dust intrusions into the local atmosphere as they intersect one of the primary export pathways of mineral dust from the Sahara. We have statistically distinguished the ? of ‘baseline’ and ‘dust-influenced’ conditions, by fitting normal–gamma mixture distributions to the observations using Markov Chain Monte Carlo methods, and then examined the seasonal and long-term characteristics of these data. The telescope data show that baseline conditions are usually stable at ?<0.1 (except during periods influenced by volcanic aerosols), and indicate the existence of a low-amplitude (? = 0.01) seasonal variation. During dust-influenced conditions ? regularly reaches values a factor of 2–6 times higher than normal. The majority of dust intrusions take place during the months of July–August, when they may occur 44 ± 15% of the time, predominantly at high-altitudes (with ~94.3 ± 1.6% of intrusions occurring ?2.4km). Whereas, during the months of November–May, dust intrusions occur far less frequently (~ 19 ± 7%), and are more common at lower altitudes—with intrusions at <2.4 km comprising ~ 79.5 ± 3.2% of all outbreaks. We find year-to-year variations in the frequency of dust-influenced conditions (of ~ 9%), but no long-term trend over the observed thirty-year period.
Early open-access version on Journal of Climate's website
Clouds are a critical component of Earth’s climate system. Although satellite-based irradiance measurements are available over approximately the past 30 years, difficulties in measuring clouds means it is unclear how global cloud properties have changed over this period. From the International Satellite Cloud Climatology Project (ISCCP) and Moderate Resolution Imaging Spectroradiometer (MODIS) datasets we have examined the validity of long-term cloud changes. We find that for both datasets, low-level (>680mb) cloud changes are largely a reflection of higher-level (≥680mb) variations. Linear trends from ISCCP also suggest that the dataset contains considerable features of an artificial origin. Despite this, an examination of ISCCP in relation to the MODIS dataset shows that over the past ten years of overlapping measurements between 60°N–60°S both datasets have been in close agreement (r = 0.63, p = 7×10−4). Over this time total cloud cover has been relatively stable. Both ISCCP and MODIS datasets show a close correspondence to Sea Surface Temperatures (SST) over the Pacific region, providing a further independent validation of the datasets.
This work was presented at the International Radiation Symposium, 2012, in Berlin.
View proceedings at AIP.
Benjamin Laken holds a Ph.D. in Physical Geography from Sussex University (England), and has been a postdoctoral researcher at institutes in Spain, and Norway. He has published numerous investigations relating to the nature, causes, and impacts of climate variability and change on the Earth system and humans, and has been a contributing author to IPCC AR5. In 2016 he worked in University College London as a Research Software Engineer, assisting researchers across disciplines improve the quality of their work through better software practices.