Lord Smith Not Resigning

[Neverwhere]

I find it quite cheering to look at the internet commentary on this subject. We tend to think the UK's turning into a nation of uneducated simpletons, but it turns out that in fact a remarkably large percentage of the population has considerable expertise on the subject of large-scale land drainage. Who'd have thought it?

[sleepwello'nights]

This Link provides an interesting summary of the Somerset flooding, with some interesting opinions in the comments.

[Tankus]

I know the emotive reaction of the farmers is that more should have been done before. Is there any evidence to support their assertion that there would have been less flooding this winter if certain rivers had been dredged?

From the EA themselves after the last flood http://test.environment-agency.gov.uk/static/documents/Leisure/Curry_Moor_options_summary_sheet_-_historic_flood_levels_and_hydraulic_modelling.pdf

Bit awkward for him

[frozen_out]

The furore reminds me of the furore a couple of years back when we had once in 30 year snowfall and ran out of grit. Why weren't we prepared?

Well if you keep enough grit for a once in 30 year event you get accused of being wasteful and keeping uneccesary inventory.

What do you do?

[Tankus]

smith promised dredging after last years floods , "lessons will be learnt "" did the reports ......then nowt.....probably too busy in his other 9 jobs

[SNACR]

Chris Smith refused to dredge the rivers of the Somerset levels because he is stupid, big headed, arrogant and lazy.

You can do nothing about the rain, but if the rivers were dredged it would run away much quicker.

is a most likely incompetent figurehead still riding the state and pseudo-state gravy train and I doubt, in reality, he has the core skills to do anything but run up debt and wouldn't be doing that without positive discrimination and diversity quotas.

Fixed, for you.

[snowflux]

This Link provides an interesting summary of the Somerset flooding, with some interesting opinions in the comments.

I wonder why the author of that piece hasn't updated it with January's rainfall in the region (over 200% of normal). Presumably because it wouldn't tie in with his AGW-denier agenda.

[The Eagle]

Well, that's not strictly true, is it? One could, say, form agreements with other nations to limit the amount of greenhouse gases being pumped into the atmosphere that lead to increased rainfall (in the UK) as well as rising sea levels.

Troll.

[snowflux]

Troll.

Idiot.

[Neverwhere]

Troll.

Clearly he's not watched enough Salby then he'd know the destruction of natural carbon sinks is causing climate change so we're all totally innocent cos humans have never destroyed any natural carbon sinks ever, we swear it guvnor, we never touched nuffin

[Nuggets Mahoney]

However people are living on flood plains and they are shocked when it does rain constantly and it floods. I wonder what the reaction would be if the EA pointed out the fact that people are living in flood plains and the idea for a flood plain is for it to flood when the river is overwhelmed. I'm sure that would trigger instant calls for resignations.

I used to live in Christchurch (NZ). It's in a tsunami zone, everyone knows it's in a tsunami zone and that it's not a matter of 'if' but when the city is going to get hit by a catastrophic wave. In spite of that, in recent years people have been merrily building, and buying, housing on reclaimed coastal marshland and floodplains. Wellington, further north, could be hit by an earthquake and fall into the ocean any time. Auckland is sitting on top of an active volcano. On the subject of volcanoes, Vesuvius is already overdue and some seismologists reckon the next significant eruption is going to be a git...

Off the top of my head I can think of maybe a dozen chunky conurbation centres that are going to cop it one of these days. Not in a million years, or ten thousand years, and not by a human induced catastrophe which has never happened before, but by periodic natural events which I don't believe anyone 'denies'. Yet people still keep building in harm's way regardless.

People are like that. Always up for a punt.

It's worth a moan after the inevitable happens though, just in case there's any compo knocking around.

[EUBanana]

Well, that's not strictly true, is it? One could, say, form agreements with other nations to limit the amount of greenhouse gases being pumped into the atmosphere that lead to increased rainfall (in the UK) as well as rising sea levels.

The Somerset levels are reclaimed land. They've always been flood prone. Reclaimed land requires maintenance. Thats what government bodies like the Environment Agency are really for!

Modern environmentalism, forget that guff, this is old hat stuff that has been going on for centuries. Only now magic fairy dust and donkey sanctuaries take precedence over the dull job of dredging rivers. The fact this is old hat is why Somerset has local drainage boards, see http://www.somersetdrainageboards.gov.uk/ , that levy drainage rates. And they, at least, seem to have been competent.

I hope the polders don't have muppets like Lord Smith in charge of their maintenance.

[EUBanana]

They were dredged in November.

Since when it has pissed it down more than it has for a long time.

They started dredging them in November, after moaning in the winter of 2012/2013. They had to stop pretty quickly because it started raining unfortunately. Too late!

It's not a task done overnight. After a decade of doing zip there's going to be a lot of silt to dredge.

[EUBanana]

It's worth a moan after the inevitable happens though, just in case there's any compo knocking around.

[crashmonitor]

There really isn't much you can do at the moment with the land flooded. The most embarrassing bit for me is the army, very much a PR exercise. Basically they have got personnel in and they clearly look a bit awkward and don't have much to do.

On the news last night we saw them building a sand bag barrier, very badly (at one point they were dismantling the mess), and seemingly ridiculously over-staffed with a line of men playing pass the bag standing about a foot apart. I think that a farmer or somebody more used to doing it would work at four times the speed with a quarter of the manpower. But it sums up the confusion.

[Frank Hovis]

There really isn't much you can do at the moment with the land flooded. The most embarrassing bit for me is the army, very much a PR exercise. Basically they have got personnel in and they clearly look a bit awkward and don't have much to do.

On the news last night we saw them building a sand bag barrier, very badly (at one point they were dismantling the mess), and seemingly ridiculously over-staffed with a line of men playing pass the bag standing about a foot apart. I think that a farmer or somebody more used to doing it would work at four times the speed with a quarter of the manpower. But it sums up the confusion.

True but it's a morale booster if you're flooded.

Proper dredging programmes and planning restrictions with regard to flooding are required.

It's not just no building in flood plains, one poor village in Devon, Harburton Forge IIRC, was fine until a big development on neighbouring high ground meant the water that used to sink into the hill now ran straight into their village and it flooded every year.

[Mr. Miyagi]

Well, that's not strictly true, is it? One could, say, form agreements with other nations to limit the amount of greenhouse gases being pumped into the atmosphere that lead to increased rainfall (in the UK) as well as rising sea levels.

Empirical evidence please.

[Olebrum]

I wonder if the Coalition will help him by cutting the budget for flood defences by another 17%?

[Frank Hovis]

Empirical evidence please.

You cannot expect empirical evidence from the disciples of the Church of Global Warming.

[ChumpusRex]

Bit awkward for him

Were there any report published about the effects of Tone/Parrett dredging on downstream areas (e.g. Bridgewater)?

We don't know the whole story without them.

[Neverwhere]

Empirical evidence please.

Increased frequency is really the key variable as extreme weather events have always occurred at infrequent intervals, the hypothesis that such extreme events increase in frequency in line with overall global temperature (i.e. not necessarily local as the two can diverge substantially due to weather system interactions and evaporated water from warmer environments can be transported vast distances by atmospheric rivers) conforms to general scientific principles and in recent years increasing numbers of studies have been published with data that broadly supports it. For instance:

Winter floods in Britain are connected to atmospheric rivers

[1] Damage from flooding in the winter and fall seasons has been widespread in the United Kingdom (UK) and Western Europe over recent decades. Here we show that winter flood events in the UK are connected to Atmospheric Rivers (ARs), narrow ribbons along which a large flux of moisture is transported from the subtropics to the mid-latitudes. Combining river flow records with rainfall measurements, satellite data and model simulations, we demonstrate that ARs occur simultaneously with the 10 largest winter flood events since 1970 in a range of British river basins, suggesting that ARs are persistently critical in explaining extreme winter flooding in the UK. Understanding the physical processes that determine the persistence of AR events will be of importance in assessing the risk of future flooding over north-western Europe and other mid-latitude regions.

Full paper available here: http://onlinelibrary...049783/abstract

Large-scale climate, precipitation and British river flows: Identifying hydroclimatological connections and dynamics

Investigation of links between large-scale climate and river basin-scale precipitation and discharge is necessary to improve understanding of the hydroclimatological process chain. This paper aims to identify the large-scale circulation variables that yield significant statistical relationships with precipitation and river flow for ten British basins, and evaluate the dependence of the strength and location of centres of climate–hydrology correlation on basin situation. Using quasi-geostrophic theory as a framework to select appropriate explanatory variables, this study undertakes ranked correlation analysis between gridded ERA-40 atmospheric data and precipitation and river flow observations at a monthly resolution over a 26 year period. Relationships between large-scale atmospheric circulation and precipitation and river flow are found to vary spatially and seasonally across Britain, with strongest associations evident in western Britain and in winter. Monthly precipitation totals and river flow demonstrate highly significant negative (positive) correlation with mean sea level pressure MSLP (Zonal Wind U), but the location of high correlation centres vary for different basins. There are weaker atmospheric links with river flow compared to precipitation, reflecting the non-linearity of the rainfall–runoff transformation and the importance of basin properties as a modifier of climate inputs. The North Atlantic Oscillation Index (NAOI) cannot capture the seasonal movement of climate–hydrology connections due to the fixed station locations used for the index calculation, and thus has weaker monthly correlations with precipitation and river flow compared to gridded ERA-40 circulation variables (and in particular the comparable MSLP).

Full paper here: http://iopscience.io...9326/8/3/034010

The detection of atmospheric rivers in atmospheric reanalyses and their links to British winter floods and the large-scale climatic circulation

[1] Atmospheric Rivers (ARs), narrow plumes of enhanced moisture transport in the lower troposphere, are a key synoptic feature behind winter flooding in midlatitude regions. This article develops an algorithm which uses the spatial and temporal extent of the vertically integrated horizontal water vapor transport for the detection of persistent ARs (lasting 18 h or longer) in five atmospheric reanalysis products. Applying the algorithm to the different reanalyses in the vicinity of Great Britain during the winter half-years of 1980–2010 (31 years) demonstrates generally good agreement of AR occurrence between the products. The relationship between persistent AR occurrences and winter floods is demonstrated using winter peaks-over-threshold (POT) floods (with on average one flood peak per winter). In the nine study basins, the number of winter POT-1 floods associated with persistent ARs ranged from approximately 40 to 80%. A Poisson regression model was used to describe the relationship between the number of ARs in the winter half-years and the large-scale climate variability. A significant negative dependence was found between AR totals and the Scandinavian Pattern (SCP), with a greater frequency of ARs associated with lower SCP values.

Full paper here: http://iopscience.io...9326/8/3/034010

Meteorological Characteristics and Overland Precipitation Impacts of Atmospheric Rivers Affecting the West Coast of North America Based on Eight Years of SSM/I Satellite Observation

The pre-cold-frontal low-level jet within oceanic extratropical cyclones represents the lower-tropospheric component of a deeper corridor of concentrated water vapor transport in the cyclone warm sector. These corridors are referred to as atmospheric rivers (ARs) because they are narrow relative to their length scale and are responsible for most of the poleward water vapor transport at midlatitudes. This paper investigates landfalling ARs along adjacent north- and south-coast regions of western North America. Special Sensor Microwave Imager (SSM/I) satellite observations of long, narrow plumes of enhanced integrated water vapor (IWV) were used to detect ARs just offshore over the eastern Pacific from 1997 to 2005. The north coast experienced 301 AR days, while the south coast had only 115. Most ARs occurred during the warm season in the north and cool season in the south, despite the fact that the cool season is climatologically wettest for both regions. Composite SSM/I IWV analyses showed landfalling wintertime ARs extending northeastward from the tropical eastern Pacific, whereas the summertime composites were zonally oriented and, thus, did not originate from this region of the tropics. Companion SSM/I composites of daily rainfall showed significant orographic enhancement during the landfall of winter (but not summer) ARs.

The NCEP–NCAR global reanalysis dataset and regional precipitation networks were used to assess composite synoptic characteristics and overland impacts of landfalling ARs. The ARs possess strong vertically integrated horizontal water vapor fluxes that, on average, impinge on the West Coast in the pre-cold-frontal environment in winter and post-cold-frontal environment in summer. Even though the IWV in the ARs is greater in summer, the vapor flux is stronger in winter due to much stronger flows associated with more intense storms. The landfall of ARs in winter and north-coast summer coincides with anomalous warmth, a trough offshore, and ridging over the Intermountain West, whereas the south-coast summer ARs coincide with relatively cold conditions and a near-coast trough. ARs have a much more profound impact on near-coast precipitation in winter than summer, because the terrain-normal vapor flux is stronger and the air more nearly saturated in winter. During winter, ARs produce roughly twice as much precipitation as all storms. In addition, wintertime ARs with the largest SSM/I IWV are tied to more intense storms with stronger flows and vapor fluxes, and more precipitation. ARs generally increase snow water equivalent (SWE) in autumn/winter and decrease SWE in spring. On average, wintertime SWE exhibits normal gains during north-coast AR storms and above-normal gains during the south-coast AR storms. The north-coast sites are mostly lower in altitude, where warmer-than-normal conditions more frequently yield rain. During those events when heavy rain from a warm AR storm falls on a preexisting snowpack, flooding is more likely to occur.

Full paper here: http://journals.amet...75/2007JHM855.1

Extreme snowfall events linked to atmospheric rivers and surface air temperature via satellite measurements

[1] Narrow bands of strong atmospheric water vapor transport, referred to as "atmospheric rivers" (ARs), are responsible for the majority of wintertime extreme precipitation events with important contributions to the seasonal water balance. We investigate relationships between snow water equivalent (SWE), precipitation, and surface air temperature (SAT) across the Sierra Nevada for 45 wintertime AR events. Analysis of assimilated and in situ data for water years 2004–2010 indicates that ARs on average generate ∼4 times daily SWE accumulation of non-AR storms. In addition, AR events contributed ∼30–40% of total seasonal SWE accumulation in most years, with the contribution dominated by just 1–2 extreme events in some cases. In situ and remotely sensed observations show that SWE changes associated with ARs are closely related to SAT. These results reveal the previously unexplored significance of ARs with regard to the snowpack and associated sensitivities of AR precipitation to SAT.

Full paper here: http://onlinelibrary...044696/abstract

Remote sources of water vapor forming precipitation on the Norwegian west coast at 60°N–a tale of hurricanes and an atmospheric river

[1] In September 2005, an extreme precipitation event occurred on the Norwegian southwest coast, which produced flooding and landslides and caused considerable infrastructure damage and loss of human life. We found that this event was triggered by the transport of tropical and subtropical moisture associated with two former hurricanes, Maria and Nate, which both underwent transition into extratropical cyclones. The two former hurricanes generated a large stream of (sub)tropical air which extended over more than 40° of latitude and across the North Atlantic Ocean and carried a large amount of moisture originally associated with hurricane Nate; a so-called atmospheric river or moisture conveyor belt. The mountains along the Norwegian coast caused a strong orographic enhancement of the precipitation associated with the moist air. A Lagrangian moisture tracking algorithm was employed to show that the evaporative source of the precipitation falling over Norway was distributed over large parts of the North Atlantic Ocean, and indeed included large contribution from the subtropics and smaller ones from the tropics. The moisture tracking algorithm was also applied over a 5-year period. It was found that (sub)tropical sources can contribute substantially to the precipitation falling in southwestern Norway throughout the year. Thus other transport mechanisms than hurricanes are important, too, for moving (sub)tropical moisture so far north. The (sub)tropical moisture source is relatively more important during the positive phase of the North Atlantic Oscillation, as well as for stronger precipitation events.

Full paper here: http://onlinelibrary...009006/abstract

Evidence for global runoff increase related to climate warming

Ongoing global climatic change initiated by the anthropogenic release of carbon dioxide is a matter of intense debate. We focus both on the impact of these climatic changes on the global hydrological cycle and on the amplitude of the increase of global and continental runoff over the last century, in relation to measured temperature increases. In this contribution, we propose an original statistical wavelet-based method for the reconstruction of the monthly discharges of worldwide largest rivers. This method provides a data-based approximation of the evolution of the annual continental and global runoffs over the last century. A consistent correlation is highlighted between global annual temperature and runoff, suggesting a 4% global runoff increase by 1 °C global temperature rise. However, this global trend should be qualified at the regional scale where both increasing and decreasing trends are identified. North America runoffs appear to be the most sensitive to the recent climatic changes. Finally, this contribution provides the first experimental data-based evidence demonstrating the link between the global warming and the intensification of the global hydrological cycle. This corresponds to more intense evaporation over oceans coupled to continental precipitation increase or continental evaporation decrease. This process finally leads to an increase of the global continental runoff.

Full paper here: http://www.sciencedi...309170804000478

Climate Change, Atmospheric Rivers, and Floods in California – A Multimodel Analysis of Storm Frequency and Magnitude Changes

Recent studies have documented the important role that "atmospheric rivers" (ARs) of concentrated near-surface water vapor above the Pacific Ocean play in the storms and floods in California, Oregon, and Washington. By delivering large masses of warm, moist air (sometimes directly from the Tropics), ARs establish conditions for the kinds of high snowlines and copious orographic rainfall that have caused the largest historical storms. In many California rivers, essentially all major historical floods have been associated with AR storms. As an example of the kinds of storm changes that may influence future flood frequencies, the occurrence of such storms in historical observations and in a 7-model ensemble of historical-climate and projected future climate simulations is evaluated. Under an A2 greenhouse-gas emissions scenario (with emissions accelerating throughout the 21st Century), average AR statistics do not change much in most climate models; however, extremes change notably. Years with many AR episodes increase, ARs with higher-than-historical water-vapor transport rates increase, and AR storm-temperatures increase. Furthermore, the peak season within which most ARs occur is commonly projected to lengthen, extending the flood-hazard season. All of these tendencies could increase opportunities for both more frequent and more severe floods in California under projected climate changes.

Full paper here: http://onlinelibrary...0546.x/abstract

Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000

Interest in attributing the risk of damaging weather-related events to anthropogenic climate change is increasing¹. Yet climate models used to study the attribution problem typically do not resolve the weather systems associated with damaging events² such as the UK floods of October and November 2000. Occurring during the wettest autumn in England and Wales since records began in 1766^{3, 4}, these floods damaged nearly 10,000 properties across that region, disrupted services severely, and caused insured losses estimated at £1.3 billion (refs 5, 6). Although the flooding was deemed a 'wake-up call' to the impacts of climate change at the time⁷, such claims are typically supported only by general thermodynamic arguments that suggest increased extreme precipitation under global warming, but fail^{8, 9} to account fully for the complex hydrometeorology^{4, 10} associated with flooding. Here we present a multi-step, physically based 'probabilistic event attribution' framework showing that it is very likely that global anthropogenic greenhouse gas emissions substantially increased the risk of flood occurrence in England and Wales in autumn 2000. Using publicly volunteered distributed computing^{11, 12}, we generate several thousand seasonal-forecast-resolution climate model simulations of autumn 2000 weather, both under realistic conditions, and under conditions as they might have been had these greenhouse gas emissions and the resulting large-scale warming never occurred. Results are fed into a precipitation-runoff model that is used to simulate severe daily river runoff events in England and Wales (proxy indicators of flood events). The precise magnitude of the anthropogenic contribution remains uncertain, but in nine out of ten cases our model results indicate that twentieth-century anthropogenic greenhouse gas emissions increased the risk of floods occurring in England and Wales in autumn 2000 by more than 20%, and in two out of three cases by more than 90%.

Full paper available here: http://www.nature.co...ature09762.html

Future changes in atmospheric rivers and their implications for winter flooding in Britain

Within the warm conveyor belt of extra-tropical cyclones, atmospheric rivers (ARs) are the key synoptic features which deliver the majority of poleward water vapour transport, and are associated with episodes of heavy and prolonged rainfall. ARs are responsible for many of the largest winter floods in the mid-latitudes resulting in major socioeconomic losses; for example, the loss from United Kingdom (UK) flooding in summer/winter 2012 is estimated to be about $1.6 billion in damages. Given the well-established link between ARs and peak river flows for the present day, assessing how ARs could respond under future climate projections is of importance in gauging future impacts from flooding. We show that North Atlantic ARs are projected to become stronger and more numerous in the future scenarios of multiple simulations from five state-of-the-art global climate models (GCMs) in the fifth Climate Model Intercomparison Project (CMIP5). The increased water vapour transport in projected ARs implies a greater risk of higher rainfall totals and therefore larger winter floods in Britain, with increased AR frequency leading to more flood episodes. In the high emissions scenario (RCP8.5) for 2074–2099 there is an approximate doubling of AR frequency in the five GCMs. Our results suggest that the projected change in ARs is predominantly a thermodynamic response to warming resulting from anthropogenic radiative forcing.

Full paper here: http://iopscience.io...9326/8/3/034010

The balance of probabilities does seem to strongly suggest that overall global temperature increases are likely to be behind increased flooding frequency. Any empirical evidence against that you're aware of? I'd be interested to read any if you have links?

Edit: formatting

[Bloo Loo]

Increased frequency is really the key variable as extreme weather events have always occurred at infrequent intervals, the hypothesis that such extreme events increase in frequency in line with overall global temperature (i.e. not necessarily local as the two can diverge substantially due to weather system interactions and evaporated water from warmer environments can be transported vast distances by atmospheric rivers) conforms to general scientific principles and in recent years increasing numbers of studies have been published with data that broadly supports it. For instance:

The balance of probabilities does seem to strongly suggest that overall global temperature increases are likely to be behind increased flooding frequency. Any empirical evidence against that you're aware of? I'd be interested to read any if you have links?

except, it appears, global temperatures are falling.

[snowflux]

Empirical evidence please.

Obviously we've been through this many, many times before, but for the benefit anyone actually interested...

In a nutshell: it is well known from experiment that gases like CO2 strongly absorb infra-red radiation and thus tend to keep the Earth warmer than it would otherwise be. We know from experiment that the strength of this effect depends on the concentration of the gas. Hence, it is reasonable to expect that increasing the concentration of CO2 in the Earth's atmosphere will also increase this insulating effect. Observations of historical data support this hypothesis: there is strong evidence that CO2 and temperature have changed in synchrony in the past, with CO2 acting to amplify the effect on the Earth's climate of small changes in solar irradiance. We also know from experiment warmer systems will give rise to more evaporation. So it seems self-evident that warming the Earth will cause more evaporation and hence more rainfall.

[snowflux]

You cannot expect empirical evidence from the disciples of the Church of Global Warming.

Pathetic.

[Neverwhere]

except, it appears, global temperatures are falling.

Really?