Local Temperature Fluctuations Research Articles

Tree-ring based summer temperature variability since 1790 CE in the Hindu Kush region of northern Pakistan.

The Hindu Kush high-altitude regions of Pakistan are currently experiencing severe consequences as a result of global warming. In this sense, increasing soil erosion and the quick melting of glaciers are two particularly evident effects. In such a scenario, understanding long-term temperature changes is crucial for making accurate forecasts about how the Hindu Kush region may experience regional temperature changes in the future. In this study, the climate tree-ring width (TRW) analysis designated a positive and significant correlation (r = 0.622, p < 0.001) between the TRW chronology and the June to September (summer) mean maximum temperature (MMT). Using the tree-ring width of Pinus wallichiana A. B. Jackson, we reconstructed summer temperatures in the Hindu Kush region from 1790 CE. Statistical analysis showed that the reconstruction model has explained 38.7% of the climate variance during the instrumental period of 1967 to 2018 CE. Five extremely warm summer periods (≥ 4 years; before the instrumental period 1967-2018 CE) of 1804-1830, 1839-1862, 1876-1879, 1905-1910, 1923-1935 CE, and six cold summer periods of 1790-1803, 1832-1838, 1863-1875, 1880-1904, 1911-1922, and 1936-1945 CE have been observed during the past 229 years. Individually, the year 1856 CE experienced severe warmth (31.85°C), whereas 1794 CE was relatively cooler (29.60°C). The spectral multi-taper method (MTM) shows significant (p < 0.05) cycles, which take place about every 9.3, 5.7, 4.2, and 3.6 years. In particular, the 9.3-year cycle, which closely aligns with the 11-year solar activity cycle, suggests a potential correlation between solar activity and local temperature fluctuations. Moreover, our reconstruction demonstrates a significant degree of consistency when compared to actual climate data and regional temperature reconstruction series, reporting a strong logic of trust in the reliability and accuracy of our findings. This evidence reaffirms that our reconstruction shows significant and dependable regional temperature signals, notably being representative for the Hindu Kush region.

Effects of ocean warming on the fatty acid and epigenetic profile of Acartia tonsa: A multigenerational approach

The effects of climate change are becoming more prevalent, and it is important to know how copepods, the most abundant class in zooplankton, will react to changing temperatures as they are the main food source for secondary consumers. They act as key transferers of nutrients from primary producers to organisms higher up the food chain. Little is known about the effects of temperature changes on copepods on the long term, i.e., over several generations. Especially the epigenetic domain seems to be understudied and the question remains whether the nutritional value of copepods will permanently change with rising water temperatures. In this research, the effects of temperature on the fatty acid and epigenetic profiles of the abundant planktonic copepod Acartia tonsa were investigated, since we expect to see a link between these two. Indeed, changing methylation patterns helped copepods to deal with higher temperatures, which is in line with the relative abundance of the most important fatty acids, e.g., DHA. However, this pattern was only observed when temperature increased slowly. A sudden increase in temperature showed the opposite effect; Acartia tonsa did not show deviant methylation patterns and the relative abundance of DHA and other important fatty acids dropped significantly after several generations. These results suggest that local fluctuations in temperature have a greater effect on Acartia tonsa than an elevation of the global mean.

Multi-decade changes in the condition index of adult Pacific oysters (Crassostrea gigas) in response to climate in a US west coast estuary

Pacific oysters (Crassostrea gigas) were introduced to the US west coast in the early 1900's, but only regularly spawned in several discrete estuarine locations like Willapa Bay where conditions allowed for adult oyster gametogenesis as well as larval survival, retention, and settlement. Oyster industry participants have long recognized that the condition of marketable oysters was related to proximity of their growing areas to the ocean. This prompted resource managers to routinely collect data and identify trends in oyster condition index (CI) in this estuary. An analysis of this almost seven- decade long CI record revealed consistent trends across four sampling locations in Willapa Bay where 50–70% of the variability in CI was explained by a single component. This component of variability in CI was related most strongly to variability in the upwelling index (UI) which was positively correlated with CI during the summer upwelling season. A relationship with the Pacific Decadal Oscillation (PDO), a broader basin-scale index of temperature was also significant, but weaker and PDO was negatively correlated with CI. Shifts or breaks in the long-term CI record occurred in 1977/78 and 1999/2000 with another shift related to the second component of variation in CI that occurred in 1988/1989. The change in 1977/78 has previously been shown to correspond with a shift in the basin scale PDO, but more recent shifts appear to be correlated with local fluctuations in both temperature and upwelling intensity. Further investigation into shifts in the seasonal timing of temperature and phytoplankton as variables that control the oyster gametogenic cycle seem warranted.

Experimental Evidence for the Existence of the Ultimate Regime in Rapidly Rotating Turbulent Thermal Convection.

What is the final state of turbulence when the driving parameter approaches infinity? For the traditional Rayleigh-Bénard convection, a possible ultimate scaling dependence of the heat transport (quantified by the Nusselt number Nu) on the Rayleigh number (Ra), which can be extrapolated to arbitrarily high Ra, is predicted by theories. The existence of the ultimate scaling has been intensively debated in the past decades. In this Letter, we adopt a novel supergravitational thermal convection experimental setup to study the possible transition to the ultimate regime. This system is characterized by the combined effects of radial-dependent centrifugal force, the Earth's gravity, and the Coriolis force. With an effective gravity up to 100 times the Earth's gravity, both Ra and shear Reynolds number can be boosted due to the increase of the buoyancy driving and the additional Coriolis forces. With over a decade of Ra range, we demonstrate the existence of ultimate regime with four direct evidences: the ultimate scaling dependence of Nu versus Ra; the appearance of the turbulent velocity boundary layer profile; the enhanced strength of the shear Reynolds number; and the new statistical properties of local temperature fluctuations. The present findings will greatly improve the understanding of the flow dynamics in geophysical and astrophysical flows.

Analysis method for calculating radial correlation length of electron temperature turbulence from correlation electron cyclotron emission radiometer.

The radial correlation length (Lr) is one of the essential quantities to measure in order to more fully characterize and understand turbulence and anomalous transport in magnetic fusion plasmas. The analysis method for calculating Lr of electron temperature (Te) turbulence from correlation electron cyclotron emission (correlation ECE or CECE) radiometer measurements has not been fully developed partly due to the fact that the turbulent electron temperature fluctuations are generally imbedded in much larger amplitude thermal noise, which leads to a greatly reduced cross correlation coefficient (ϱ) between two spatially separated ECE signals. This work finds that this ϱ reduction factor due to thermal noise is a function of the local relative temperature fluctuation power and CECE system bandwidths of intermediate and video frequencies, independent of radial separations. This indicates that under the approximation of constant relative temperature fluctuation power for a small radial range of local CECE measurements, the original shape of ϱ as a function of radial separation without thermal noise is preserved in the CECE data with thermal noise present. For Te turbulence with a Gaussian radial wavenumber spectrum, a fit function using the product of Gaussian and sinusoidal functions is derived for calculating Lr. This analysis method has been numerically tested using simulated ECE radiometer data over a range of parameters. Using this method, the experimental temperature turbulence correlation length Lr in a DIII-D L-mode plasma is found to be ∼10 times the local ion gyroradius.

Construction of multiple anti-resonant light guidance mechanisms in a hollow-core fiber structure for simultaneous measurement of multiple parameters.

The construction of multiple light guidance mechanisms in a hollow-core fiber (HCF) structure is a popular way to realize the simultaneous measurement of multiple parameters. In this work, a partial coating method to excite multiple anti-resonant light guidance mechanisms (ARLGMs) in an HCF structure for the simultaneous measurement of multiple parameters is proposed. As an example, a double ARLGM based on a partially polyimide (PI)-coated HCF structure for the simultaneous measurement of relative humidity (RH) and temperature is demonstrated theoretically and experimentally. The dip (dip II) produced by the PI-coated HCF section shifts linearly with surrounding RH changes with a sensitivity of circa 58.6 ± 0.77 pm/%RH, while the dip (dip I) produced by the bare HCF section (with an air coating layer) is insensitive to RH changes. In addition, both types of dips have linear responses to temperature variations, with similar sensitivities of ∼ 17 pm/°C. Hence, the proposed sensor structure can be used as an RH sensor that is also capable of compensating for local temperature fluctuations. More importantly, the simultaneous measurement of multiple parameters (such as biomarkers) is possible using the proposed method provided the proper sensing materials are partially coated onto the HCF surface.

Dynamics of the refractive index in Langmuir monolayers.

We present theoretical description of dynamics of the refractive index in Langmuir monolayers subjected to continuous-wave (CW) laser radiation, using the mechanism of the local temperature fluctuations. Such mechanism can be applied to all monolayer systems that consist of rodlike molecules. The CW laser radiation induces conformational transitions of molecules in monolayer, which, after some time being in the excited state, come back into the ground state, thus renewing their initial shape and releasing energy into the medium, locally heating it. This leads to the local temperature change, which promotes new conformational transitions of molecules. Such nonlinear energy redistribution mechanism permits the conformational transition boundary to move. The existence of the transitions is seen from the change of the refractive index.

Sub-Kelvin thermometry for evaluating the local temperature stability within in situ TEM gas cells

In situ TEM utilizing windowed gas cells is a promising technique for studying catalytic processes, wherein temperature is one of the most important parameters to be controlled. Current gas cells are only capable of temperature measurement on a global (mm) scale, although the local temperature at the spot of observation (µm to nm scale) may significantly differ. Thus, local temperature fluctuations caused by gas flow and heat dissipation dynamics remain undetected when solely relying on the global device feedback. In this study, we overcome this limitation by measuring the specimen temperature in situ utilizing parallel-beam electron diffraction at gold nanoparticles. By combining this technique with an advanced data processing algorithm, we achieve sub-Kelvin precision in both, vacuum as well as gaseous environments. Mitigating charging effects is furthermore shown to minimize systematic errors. By utilizing this method, we characterize the local thermal stability of a state-of-the-art gas cell equipped with heating capability in vacuum and under various gas-flow conditions. Our findings provide crucial reference for in situ investigations into catalysis.

Basic Study on Prediction of Wall Temperature Fluctuation due to Boiling

In this study, temporal fluctuation of the boiling heat transfer was simply modeled based on measurements, and unsteady heat conduction simulations were conducted using this model as a boundary condition. As a result, it was found that the wall surface temperature fluctuation varies significantly depending on the thermophysical properties of the heat transfer surface. It was also shown that the amplitude of the surface-averaged wall temperature fluctuation over a typical area varies inversely proportional to the thermal effusivity √cρλ. However, the simplified model of heat transfer fluctuation is used to predict local temperature fluctuations, the prediction accuracy is degraded due to thermal diffusion in the plane direction. Therefore, in order to improve the accuracy to predict local wall temperature fluctuations, it is necessary to properly model the surface distribution of heat transfer coefficient in addition to the temporal fluctuation.

Internal Wave Imprints on Temperature Fluctuations as Revealed by Rapid‐Sampling Deep Profiling Floats

AbstractInternal waves play important roles in modulating the temperature variations and heat transfers in stratified oceans. However, due to the deep ocean measuring approach limitations, it is still challengeable to characterize the temperature fluctuations induced by internal waves in the deep oceans below 2,000 m. In this study, a fleet of rapid‐sampling deep profiling floats with an approximately daily sampling rate was deployed in the northeastern South China Sea (SCS), Philippine Basin (PB), Mariana Arc (MA), and Kuroshio Extension (KE). Results show that the internal waves, internal tides or near‐inertial waves, have considerable imprints on local temperature fluctuations. Geographically, the internal wave induced temperature fluctuations are generally larger in the PB and MA, indicative of a strong deep signature of internal tides generated by local energetic tide‐topography interactions or radiation from remote sources. The temperature fluctuations at 4,000 m can reach up to 7 m°C in most regions, which may cover up real signals of temperature change, posing challenges to assess the deep ocean warming rate through currently insufficient deep profiling floats. Besides, the amplitude of isopycnal displacement in the PB and MA is evidently larger than in KE at 4,000 m, which implies enhanced diapycnal diffusivity and mixing in the deep layers of open oceans with rough topography.

Universal scaling of temperature variance in Rayleigh–Bénard convection near the transition to the ultimate state

We report measurements of the temperature frequency spectra $P(\,f, z, r)$ , the variance $\sigma ^2(z,r)$ and the Nusselt number $Nu$ in turbulent Rayleigh–Bénard convection (RBC) over the Rayleigh number range $4\times 10^{11} \underset{\smash{\scriptscriptstyle\thicksim}} { &lt; } Ra \underset{\smash{\scriptscriptstyle\thicksim}} { &lt; } 5\times 10^{15}$ and for a Prandtl number $Pr \simeq ~0.8$ ( $z$ is the vertical distance from the bottom plate and $r$ is the radial position). Three RBC samples with diameter $D = 1.12$ m yet different aspect ratios $\varGamma \equiv D/L = 1.00$ , $0.50$ and $0.33$ ( $L$ is the sample height) were used. In each sample, the results for $\sigma ^2/\varDelta ^2$ ( $\varDelta$ is the applied temperature difference) in the classical state over the range $0.018 \underset{\smash{\scriptscriptstyle\thicksim}} { &lt; } z/L \underset{\smash{\scriptscriptstyle\thicksim}} { &lt; } 0.5$ can be collapsed onto a single curve, independent of $Ra$ , by normalizing the distance $z$ by the thermal boundary layer thickness $\lambda = L/(2 Nu)$ . One can derive the equation $\sigma ^2/\varDelta ^2 = c_1\times \ln (z/\lambda )+c_2+c_3(z/\lambda )^{-0.5}$ from the observed $f^{-1}$ scaling of the temperature frequency spectrum. It fits the collapsed $\sigma ^2(z/\lambda )$ data in the classical state over the large range $20 \underset{\smash{\scriptscriptstyle\thicksim}} { &lt; } z/\lambda \underset{\smash{\scriptscriptstyle\thicksim}} { &lt; } 10^4$ . In the ultimate state ( $Ra \underset{\smash{\scriptscriptstyle\thicksim}} { &gt; } Ra^*_2$ ) the data can be collapsed only when an adjustable parameter $\tilde \lambda = L/(2 \widetilde {Nu})$ is used to replace $\lambda$ . The values of $\widetilde {Nu}$ are larger by about 10 % than the experimentally measured $Nu$ but follow the predicted $Ra$ dependence of $Nu$ for the ultimate RBC regime. The data for both the global heat transport and the local temperature fluctuations reveal the ultimate-state transitions at $Ra^*_2(\varGamma )$ . They yield $Ra^*_2 \propto \varGamma ^{-3.0}$ in the studied $\varGamma$ range.

Non-Interventional and High-Precision Temperature Measurement Biochips for Long-Term Monitoring the Temperature Fluctuations of Individual Cells.

Monitoring the thermal responses of individual cells to external stimuli is essential for studies of cell metabolism, organelle function, and drug screening. Fluorescent temperature probes are usually employed to measure the temperatures of individual cells; however, they have some unavoidable problems, such as, poor stability caused by their sensitivity to the chemical composition of the solution and the limitation in their measurement time due to the short fluorescence lifetime. Here, we demonstrate a stable, non-interventional, and high-precision temperature-measurement chip that can monitor the temperature fluctuations of individual cells subject to external stimuli and over a normal cell life cycle as long as several days. To improve the temperature resolution, we designed temperature sensors made of Pd–Cr thin-film thermocouples, a freestanding Si3N4 platform, and a dual-temperature control system. Our experimental results confirm the feasibility of using this cellular temperature-measurement chip to detect local temperature fluctuations of individual cells that are 0.3–1.5 K higher than the ambient temperature for HeLa cells in different proliferation cycles. In the future, we plan to integrate this chip with other single-cell technologies and apply it to research related to cellular heat-stress response.

Understanding drivers of glacier-length variability over the last millennium

Abstract. Changes in glacier length reflect the integrated response to local fluctuations in temperature and precipitation resulting from both external forcing (e.g., volcanic eruptions or anthropogenic CO2) and internal climate variability. In order to interpret the climate history reflected in the glacier moraine record, the influence of both sources of climate variability must therefore be considered. Here we study the last millennium of glacier-length variability across the globe using a simple dynamic glacier model, which we force with temperature and precipitation time series from a 13-member ensemble of simulations from a global climate model. The ensemble allows us to quantify the contributions to glacier-length variability from external forcing (given by the ensemble mean) and internal variability (given by the ensemble spread). Within this framework, we find that internal variability is the predominant source of length fluctuations for glaciers with a shorter response time (less than a few decades). However, for glaciers with longer response timescales (more than a few decades) external forcing has a greater influence than internal variability. We further find that external forcing also dominates when the response of glaciers from widely separated regions is averaged. Single-forcing simulations indicate that, for this climate model, most of the forced response over the last millennium, pre-anthropogenic warming, has been driven by global-scale temperature change associated with volcanic aerosols.

Significant Shift of Ambient Night-Time Air Temperature during Rice Growing Season in Major US Rice States

Heat stress studies in rice (Oryza sativa sp.) under extreme weather scenarios generally use constant temperatures to influence the crop responses without relation to actual weather changes. These heat stress studies may have limited implications for future crop yields because elevated temperatures are not based on local temperature fluctuations. This study investigated the night-time air temperature pattern and assessed the status and reliability of available weather station data in four major rice growing states; Arkansas (AR), California (CA), Louisiana (LA) and Texas (TX) using four public weather station databases. Hourly and daily night-time air temperatures from 20:00 to 06:00 were obtained from 1940 to 2018 during the rice growing period. During the 67-year period, a significant increase of 1.12°C and 0.53°C in seasonal night air temperature occurred in CA and AR (P ≤ 0.001) while LA and TX showed minimal to no increase in night air temperature. Across all rice states and years, night air temperature fluctuations ranged between ±0.2°C and ±4°C with the greatest occurred in CA (2.9°C) and AR (4.5°C). Mean night-time air temperature across all states ranged from 22.6°C to 29.5°C with a rate of increase of 0.01°C to 0.02°C per year since 1941. Due to a relatively smaller spatial dataset (from 1941-2018), trend analyses for AR, TX and LA showed modest bias with root mean square errors (RMSE) of 0.5°C to 1.1°C of absolute mean temperature across all locations. Results in this study showed seasonal night-time air temperature change occurred in some major US rice producing states during the last 67-years. This study highlights the need for more weather stations near agricultural farms to reliably derive actual temperature patterns in the rice growing regions.

Multistimuli-Responsive Optical Hydrogel Nanomembranes to Construct Planar Color Display Boards for Detecting Local Environmental Changes.

Planar metal-insulator-metal (MIM) optical cavities are attractive for biochemical and environmental sensing applications, as they offer a cost-effective cavity platform with acceptable performances. However, localized detection and scope of expansion of applicable analytes are still challenging. Here, we report a stimuli-responsive color display board that can exhibit local spectral footprints, for locally applied heat and alcohol presence. A thermoresponsive, optically applicable, and patternable copolymer, poly(N-isopropylacrylamide-r-glycidyl methacrylate), is synthesized and used with a photosensitive cross-linker to produce a responsive insulating layer. This layer is then sandwiched between two nanoporous silver membranes to yield a thermoresponsive MIM cavity. The resonant spectral peak is blue-shifted as the environmental temperature increases, and the dynamic range of the resonant peak is largely affected by the composition and structure of the cross-linker and the copolymer. The localized temperature increase of silk particles with gold nanoparticles by laser heating can be measured by reading the spectral shift. In addition, a free-standing color board can be transferred onto a curved biological tissue sample, allowing us to simultaneously read the temperature of the tissue sample and the concentration of ethanol. The stimuli-responsive MIM provides a new way to optically sense localized environmental temperature and ethanol concentration fluctuations.

A Case Study Balancing Predetermined Targets and Real-World Constraints to Guide Optimum Urban Tree Canopy Cover for Perth, Western Australia

Trees in urban settings are becoming increasingly important as mediators to emerging challenges that transect social, environmental, and economic factors. Trees provide shade; absorb and store atmospheric carbon and other pollutants; reduce local temperature fluctuations; provide essential inner-city fauna habitat; assist in reducing over-land stormwater flow; provide amenity; and provide many more social, environmental, and economic benefits. To secure these benefits, tree canopy cover targets are commonly employed by land managers; however, such targets are rarely quantified against the characteristics and limitations of individual urban centers. Through the generation and interrogation of qualitative and quantitative data, this case study of Perth, Western Australia presents a new conceptual tool that integrates eleven factors found to influence the capacity and opportunity for a city to support urban tree canopy cover. This tool is designed to capture and causally weigh urban tree canopy considerations based on individual city characteristics, collective values, and identifiable constraints. The output of the tool provides an “optimum” tree canopy cover result (as a percentage of the urban fabric) to better inform canopy cover targets and recommendations for urban tree strategic planning and management. This tool is valuable for urban land managers, city planners, urban designers, and communities in effective planning, management, valuation, and investment regarding urban trees as a sub-set of urban green infrastructure.

Management of surface cooling non-uniformity in spray cooling

The existence of the hot spot area in the impact center of spray cooling indicates that the temperature is not uniform on a relative large spray-covered surface. In this study, the temperature distribution on a large spray-cooled surface is experimentally studied, and cooling non-uniformity (CNU) is defined to quantify the global and local temperature fluctuations. A flat thin film heater is newly designed, and surface temperature is measured using high-resolution infrared thermography. Particle Imaging Velocimetry (PIV) is used to acquire the droplet velocity of the spray. In the present work, three methods are investigated to reduce the CNU. One method is to change the height, the vertical spacing between the spray nozzle and surface. It is found that with the increasing spray height, the CNU first decreases to the lowest point and then rises to the peak value. The second method is to incline the spray. It is discovered that inclined spray impact benefits the cooling uniformity at the larger spray height. The third method is spray-jet cooling, in which a liquid jet is added to impinge at the center of the spray cooling. It shows that the spray-jet cooling does not only reduce CNU but also increases CHF.

Spatio-Temporal Analysis of Urban Heatwaves Using Tukey g-and-h Random Field Models

Real-time heatwave risk management with fine-grained spatial resolution is important for analysis of urban heat island (UHI) effects and local heatwaves. This study analyzed the spatio-temporal behavior of ground temperatures and developed methods for modeling them. The developed models consider two higher-order stochastic spatial properties (skewness and kurtosis), which are key to understanding and describing local temperature fluctuations and UHI effects. Application of the developed models to the greater Tokyo metropolitan area demonstrated the feasibility of statistically incorporating a variety of real datasets. Remotely sensed imagery and data from a variety of ground-based monitoring sites were used to build models linking urban covariates to air temperature. Air temperature models were used to capture high-resolution spatial emulator outputs for modeling ground surface temperatures. The main processes studied were the Tukey g-and-h processes for capturing spatial and temporal aspects of heat processes in urban environments. The main finding is that consideration of not only the mean temperature but also the variance, skewness, and kurtosis parameters can reveal hidden heatwave structures.

Short Circuit Capability Characterization and Analysis of p-GaN Gate High-Electron-Mobility Transistors Under Single and Repetitive Tests

Short circuit (SC) capability of 650-V Schottky-type p-GaN gate high-electron-mobility transistors (HEMTs) under single and repetitive tests is characterized in this article. The investigated devices exhibit strong capability under a single SC test, but weak capability under repetitive SC tests with a bus voltage of 400 V and a gate drive voltage of 6 V. The failure mechanism under repetitive SC tests is revealed through electrothermal simulation and microscale failure spot analysis. Thermal fatigue cracks are formed due to the high temperature spike and local temperature fluctuations in the narrow GaN channel and buffer layers, leading to weak repetitive SC capability. The unique heat confinement effect in the GaN layer plays an important role in the formation of high temperature spike and fatigue cracks. The withstand time in a single SC test is several hundred microseconds due to fast drain current drop that results from high temperature and, to a lesser degree, the dynamic threshold voltage shift during the SC transient. The device failure in a single-event SC test is related to heat diffusion to a wider region. Some guidelines are proposed for handling and improving the repetitive SC capability.

The Anatomy of a Mississippian (Viséan) carbonate platform interior, UK: Depositional cycles, glacioeustasy and facies mosaics

Late Viséan platform interior carbonate strata of northern England and Wales have traditionally been interpreted to comprise shallowing-up cyclothems, the upper boundaries of which are marked by unconformities that record subaerial exposure events. These strata were deposited during what is understood to be a greenhouse-to-icehouse transition, and the cyclothems are assumed to reflect glacioeustatic sea-level oscillations associated with this climatic change. Importantly, these interpretations reflect a qualitative model which assumes that facies respond in a simple way to water depth variations and so migrate and stack in a predictable pattern as eustatic sea-level fluctuates. Exposure surfaces and most facies are, however, laterally discontinuous across the platform tops. Quantitative statistical analysis and simple 1D stratigraphic forward modelling suggest that the observed vertical facies stacking patterns on the Derbyshire and North Wales Platforms are not cyclical. The most ordered arrangement of facies that could be interpreted as “ideal cycles” in each section are variable within and across the platforms. This observational and analytical evidence suggests that instead of a simple, dominant external glacioeustatic forcing on sedimentation, a model commonly proposed for the Late Viséan carbonate strata of northern England and Wales, strata were deposited as a facies mosaic, under variable hydrodynamic conditions influenced by autogenic processes as well as local environmental fluctuations in salinity and temperature, and perhaps in conjunction with glacioeustasy and syn-rift tectonic processes which occurred from metre-scale to kilometre-scale, as suggested by the ideal cycles.