Intraseasonal Patterns Research Articles

Fine scale assessment of seasonal, intra-seasonal and spatial dynamics of soil CO2 effluxes over a balsam fir-dominated perhumid boreal landscape

Total soil CO2 efflux (FCO2) is the second most important carbon flux after photosynthesis in boreal forests. However, accurate modelling of FCO2 remains challenging because of its high variability, both temporally and spatially. Using an Abies balsamea-dominated boreal landscape in Quebec (eastern Canada) as a case study, we modelled seasonal, intra-seasonal and spatial variability of FCO2 using climate variables and topographic and canopy structure attributes derived from Light Detection and Ranging (LiDAR) and assessed their respective contributions to soil CO2 emissions. Weekly point measurements of FCO2 at 99 sites were taken over an area of 122 ha between June and October 2020. The seasonal component of FCO2 was quantified and subtracted from FCO2 measurements to isolate the spatial and intra-seasonal components of the flux. The two components were then modelled using a Random Forest Regression model and studied using accumulated local effect plots (ALE plots). Our approach explained 81% of the variation in FCO2: the seasonal pattern explained 36% of the variation in FCO2 measurements, while spatial and intra-seasonal patterns together explained 45%. The most important factors explaining spatial variation were vegetation height and the slope height. Average air temperature of the last two days before efflux measurements was the most important factor explaining intra-seasonal variation. The proposed methodology makes it possible to predict FCO2 from external factors derived from climate and remote sensing data and enables the decomposition of FCO2 into its seasonal, intra-seasonal and spatial components. Our results demonstrate the importance of spatial and intra-seasonal variations in FCO2 compared to seasonal variation, a finding that has implications for the measurement and modelling of FCO2 at landscape and global scales.

Unravelling δ13C signal in Scots pine trees for climate change and tree physiology studies

Stable carbon isotope composition (δ13C) recorded in trees responds sensitively to the changing environmental conditions and thus provides a powerful tool for paleoenvironmental reconstructions. The retrospective interpretation of tree δ13C signal depends on comprehensive understanding of how environmental and physiological signals are recorded in δ13C during photosynthesis and how the δ13C signal is modified after photosynthesis. This thesis aims to improve the understanding of photosynthetic and post-photosynthetic isotope fractionation processes, and to examine the suitability of tree ring δ13C for intra-seasonal reconstructions of intrinsic water use efficiency (iWUE). The former goal was studied by combining compound-specific isotope analysis of organic matter with isotope discrimination models and online δ13C measurements of leaf CO2 fluxes for field-grown mature Scots pine (Pinus sylvestris L.). The latter was achieved via comparing 18-year-long intra-seasonal iWUE chronologies estimated from laser ablation derived tree ring δ13C, gas exchange and eddy covariance data. Mesophyll conductance and time-integral effect of leaf assimilates had a clear impact on the intra-seasonal dynamics of leaf sugar δ13C. No significant use of reserves was observed for biomass growth of needles, stem or roots of Scots pine. Unlike sucrose, leaf bulk matters had a significant δ13C offset from new assimilates, leading to a distorted environmental signal documented in their δ13C. The reliability of tree ring δ13C data for intra-seasonal iWUE reconstructions was supported by an agreement of intra-seasonal patterns across the iWUE estimation methods. These results broaden our knowledge of the less well-known photosynthetic and post-photosynthetic isotopic fractionation processes, demonstrate the benefits of analysing sucrose δ13C for understanding plant physiological responses, and show that the tree ring δ13C based iWUE reconstructions can be extended to intra-seasonal scale. This information not only helps to better unravel δ13C signal in trees, but also improves reliable reconstructions of environmental and physiological signals from tree ring δ13C.

Effects of various cutting treatments and topographic factors on microclimatic conditions in Dinaric fir-beech forests

Forest microclimate is strongly affected by local topography and management activities, as these directly alter overstory structure. In the present work we analysed the dependence of observed patterns of spatio-temporal microclimatic variations on topographic, canopy- and management-related factors. A forestry experiment was conducted in managed fir-beech forests in the Dinaric Mountains (Slovenia), which are characterized by rugged karstic terrain with numerous sinkholes. In 2012, cutting treatments representing a range in the intensity of overstory removal were performed: uncut controls (CON), 50% cut of stand growing stock (intermediate management intensity – IMI) and 100% cut (high management intensity – HMI) creating 0.4 ha canopy gaps. Fine-scale variation in aspect and slope and its effects on microclimate was assessed by comparing central, south-facing and north-facing within-sinkhole positions. We measured microclimatic variables (air temperature – T, relative humidity – RH) 0.5 m above the ground over three consecutive post-treatment growing seasons. Microclimatic variables showed an increase (T and vapour pressure deficit – VPD) or decrease (RH) with management intensity. Daily Tmax and VPDmax in HMI treatment were up to 5.9°C (on average 3.5°C) and up to 1.4 kPa (on average 0.6 kPa) higher than those in CON treatment, respectively, whereas daily RHmin was up to 22.7 (on average 13.0) percentage points lower. Regarding intra-seasonal patterns, microclimatic differences between treatments were largest during the summer. South-facing plots in the HMI treatment overall exhibited the most extreme conditions, i.e. the highest Tmax and lowest RHmin. Differences in microclimate between treatments were strongly modulated by canopy cover. The results also suggest that overstory removal increases topography-mediated variation in microclimate, as evidenced by significant differences in T, RH and VPD along the fine-scale topographic gradient within the created canopy gaps.

Intraseasonal variability of the equatorial Pacific Ocean and its relationship with ENSO based on Self-Organizing Maps analysis

We investigated the intraseasonal variability of equatorial Pacific subsurface temperature and its relationship with El Nino-Southern Oscillation (ENSO) using Self-Organizing Maps (SOM) analysis. Variation in intraseasonal subsurface temperature is mainly found along the thermocline. The SOM patterns concentrate in basin-wide seesaw or sandwich structures along an east-west axis. Both the seesaw and sandwich SOM patterns oscillate with periods of 55 to 90 days, with the sequence of them showing features of equatorial intraseasonal Kelvin wave, and have marked interannual variations in their occurrence frequencies. Further examination shows that the interannual variability of the SOM patterns is closely related to ENSO; and maxima in composite interannual variability of the SOM patterns are located in the central Pacific during CP El Nino and in the eastern Pacific during EP El Nino. These results imply that some of the ENSO forcing is manifested through changes in the occurrence frequency of intraseasonal patterns, in which the change of the intraseasonal Kelvin wave plays an important role.

A 3\u2009km spatially and temporally consistent European daily soil moisture reanalysis from 2000 to 2015

High-resolution soil moisture (SM) information is essential to many regional applications in hydrological and climate sciences. Many global estimates of surface SM are provided by satellite sensors, but at coarse spatial resolutions (lower than 25 km), which are not suitable for regional hydrologic and agriculture applications. Here we present a 16 years (2000–2015) high-resolution spatially and temporally consistent surface soil moisture reanalysis (ESSMRA) dataset (3 km, daily) over Europe from a land surface data assimilation system. Coarse-resolution satellite derived soil moisture data were assimilated into the community land model (CLM3.5) using an ensemble Kalman filter scheme, producing a 3 km daily soil moisture reanalysis dataset. Validation against 112 in-situ soil moisture observations over Europe shows that ESSMRA captures the daily, inter-annual, intra-seasonal patterns well with RMSE varying from 0.04 to 0.06 m3m−3 and correlation values above 0.5 over 70% of stations. The dataset presented here provides long-term daily surface soil moisture at a high spatiotemporal resolution and will be beneficial for many hydrological applications over regional and continental scales.

Drivers of Intra-Seasonal Variation in Black Tern (Chlidonias niger) Nest Survival

Intra-seasonal changes in depredation influence nest survival, but this may be mediated by the foraging behavior of predators or seasonal variability in habitat features. Intra-seasonal differences in factors influencing daily nest survival rates of Black Terns (Chlidonias niger) were studied in southern Ontario, Canada, during May-August 2015 and 2016. Survival of early and late-nesting individuals in relation to nest-specific temporal and spatial characteristics was investigated, including nest habitat change over the nesting cycle. The daily nest survival rate for early nesters (n = 112) declined with increasing nest age (β = -14.97; P = < 0.001), and rose with increased proportion of vegetation (β = 0.01; P = 0.02) and increased conspecific nest spacing (β = 0.01; P = 0.04). Daily nest survival rate for late nesters (n = 80) was influenced by increasing nest age (β = -12.99; P = < 0.001), with a decline during the nestling stage, and no habitat or spatial correlates. A propensity toward smaller clutch sizes with diminished survival in the late season (β = 0.67; P = 0.01) further highlights intra-seasonal differences in factors that affect survival. Predator foraging behavior may influence intra-seasonal survival patterns more than seasonal variability in habitat features.

Riding waves of intra-seasonal demand in surf tourism: analysing the nexus of seasonality and 21st century surf forecasting technology

ABSTRACTThis study examines the natural component of seasonality in surf tourism. Using survey responses collected globally, we first analyse how surfers report using forecasts to make travel decisions. Occupancy and head-count data were also collected in Pavones, Costa Rica and analyzed against surf forecast data to empirically assess intra-seasonal fluctuations. Despite a small and highly skilled subset of the surf population, most international travel is booked months in advance based on climatic factors. Case study results indicate, however, that intra-seasonal travel behaviour within a country is correlated to both mid-range (occupancy) and short range (head-counts in the water) forecasts. Combined, surf forecasts and observed natural conditions impact surf travel behaviours in nuanced ways that deserve further attention to better understand destination and hospitality management, as well as, host and guest satisfaction and how they relate to intra-seasonal and intra-regional travel patterns.

Intraseasonal patterns in coastal plankton biomass off central Chile derived from satellite observations and a biochemical model

Abstract Subseasonal (5–130 days) environmental variability can strongly affect plankton dynamics, but is often overlooked in marine ecology studies. We documented the main subseasonal patterns of plankton biomass in the coastal upwelling system off central Chile, the southern part of the Humboldt System. Subseasonal variability was extracted from temporal patterns in satellite data of wind stress, sea surface temperature, and chlorophyll from the period 2003–2011, and from a realistically forced eddy-resolving physical-biochemical model from 2003 to 2008. Although most of the wind variability occurs at submonthly frequencies (

동아시아의 겨울철 일평균 기온 변화에 나타난 계절 내 변동 유형의 종관 특성

동아시아의 겨울철 일평균 기온 변화에 나타난 계절 내 변동 유형의 종관 특성

Regional and intraseasonal variation in diet of wintering and staging Atlantic brant

Regional and intraseasonal patterns of food use influence populations through impacts on breeding success, survival, and distribution of individuals. We used both traditional foregut content analysis and stable carbon and nitrogen isotopes in liver and leg muscle to determine intraseasonal patterns in the diet of Atlantic brant geese (Branta bernicla hrota) from early winter through spring staging (1 Dec–31 May 2007–2008) along the mid-Atlantic coast of the United States. Overall, brant diet consisted of macroalgae (52%), salt marsh cordgrass (22%), eelgrass (18%), and terrestrial grass and clover (8%). Mean δ13C and δ15N values differed among these 4 food sources. Therefore, we used an isotope mixing-model (SIAR) to estimate the relative contributions of each source to brant diet among regions and months. Wintering brant in northern and southern regions ate mostly macroalgae throughout the wintering period and ate more salt marsh and terrestrial grasses in spring. Brant in central regions had a more stable diet from December to May. Regional and intraseasonal patterns in brant diet are likely affected by several factors including variation in food source availability and quality due to synergistic effects of long-term annual and intraseasonal changes in abundance of submerged aquatic vegetation. Our estimates of diet combined with information on brant daily energy requirements and forage quality can be used to more accurately determine carrying capacity of wintering brant geese given established population objectives. © 2014 The Wildlife Society.

Spawning site selection and contingent behavior in Common Snook, Centropomus undecimalis.

Reproductive behavior affects spatial population structure and our ability to manage for sustainability in marine and diadromous fishes. In this study, we used fishery independent capture-based sampling to evaluate where Common Snook occurred in Tampa Bay and if it changed with spawning season, and passive acoustic telemetry to assess fine scale behavior at an inlet spawning site (2007–2009). Snook concentrated in three areas during the spawning season only one of which fell within the expected spawning habitat. Although in lower numbers, they remained in these areas throughout the winter months. Acoustically-tagged snook (n = 31) showed two seasonal patterns at the spawning site: Most fish occurred during the spawning season but several fish displayed more extended residency, supporting the capture-based findings that Common Snook exhibit facultative catadromy. Spawning site selection for iteroparous, multiple-batch spawning fishes occurs at the lifetime, annual, or intra-annual temporal scales. In this study we show colonization of a new spawning site, indicating that lifetime spawning site fidelity of Common Snook is not fixed at this fine spatial scale. However, individuals did exhibit annual and intra-seasonal spawning site fidelity to this new site over the three years studied. The number of fish at the spawning site increased in June and July (peak spawning months) and on new and full lunar phases indicating within population variability in spawning and movement patterns. Intra-seasonal patterns of detection also differed significantly with sex. Common Snook exhibited divergent migration tactics and habitat use at the annual and estuarine scales, with contingents using different overwintering habitat. Migration tactics also varied at the spawning site at the intra-seasonal scale and with sex. These results have important implications for understanding how reproductive behavior affects spatio-temporal patterns of fish abundance and their resilience to disturbance events and fishing pressure.

Rainfall and cave water isotopic relationships in two South-France sites

This article presents isotopic measurements (δ18O and δD) of precipitation and cave drip water from two sites in southern France in order to investigate the link between rainfall and seepage water, and to characterize regional rainfall isotopic variability. These data, which are among the longest series in France, come from two rainfall stations in south-west France (Le Mas 1996–2012, and Villars 1998–2012; typically under Atlantic influence), and from one station in the south-east (Orgnac 2000–2012; under both Mediterranean and Atlantic influence). Rainfall isotopic composition is compared to drip water collected under stalactites from the same sites: Villars Cave (four drip stations 1999–2012) in the south-west, and Chauvet Cave (two drip stations 2000–2012) in the south-east, near Orgnac. The study of these isotopic data sets allows the following conclusions to be drawn about the rainfall/drip water relationships and about rainfall variability: (1) the cave drip water isotopic composition does not show any significant changes since the beginning of measurements; in order to explain its isotopic signature it is necessary to integrate weighted rainfall δ18O of all months during several years, which demonstrates that, even at shallow depths (10–50m), cave drip water is a mixture of rain water integrated over relatively long periods, which give an apparent time residence from several months to up to several years. These results have important consequences on the interpretation of proxies like speleothem fluid inclusions and tree-ring cellulose isotopic composition, which are used for paleoclimatic studies; (2) in the Villars Cave, where drip stations at two different depths were studied, lower δ18O values were observed in the lower galleries, which might be due to winter season overflows during infiltration and/or to older rain water with a different isotopic composition that reaches the lower galleries after years; (3) local precipitation is characterized by local meteoric water lines, LMWL, with δ18O/δD slopes close to 7 in both areas, and correlations between air temperature and precipitation δ18O are low at both monthly and annual scales, even with temperature weighted by the amount of precipitation; (4) the mesoscale climate model REMOiso, equipped with a water isotope module, allows the direct comparison of modeled and observed long term water isotope records. The model slightly overestimates rainfall δ18O at the respective sampling stations. However, it simulates very well not only the seasonal rainfall isotopic signal but also some intra-seasonal patterns such as a typical double-peak δ18O pattern in winter time.

Island Life Shapes the Physiology and Life History of Eastern Bluebirds (Sialia sialis)

Abstract Island organisms face a range of extrinsic threats to their characteristically small populations. Certain biological differences between island and continental organisms have the potential to exacerbate these threats. Understanding how island birds differ from their continental relatives may provide insight into population viability and serve as a predictive tool for conservation efforts. We compared an eastern bluebird population in Ohio with a threatened population in Bermuda in terms of the birds' development, morphology, immunology, and reproduction. These comparisons revealed that island nestlings had shorter wings and island adults had longer wings than their continental analogs. Island nestlings also had shorter tarsi than continental nestlings at day 8 posthatch, but this difference was absent at day 15 and in adults. Adults weighed less in Bermuda than in Ohio, and both nestlings and adults in Bermuda exhibited higher levels of two immunological indexes (concentrations of an acute-phase protein and titers of nonspecific antibodies). Clutch sizes and hatch rates did not differ between the island and continental populations; however, as the breeding season progressed, brood sizes declined in Bermuda, whereas no such decline occurred in Ohio. Despite these differences and differences in nestling development, island and continental parents fed their nestlings at equal rates. Overall, our results suggest that the Bermuda phenotype may be adjusted to certain aspects of the island environment but not to others. Efforts to conserve the bluebirds of Bermuda may be improved by focusing on the intraseasonal patterns in nestling mortality and, more generally, the survival probabilities of different age classes.

An Objectively Determined Blocking Index and its Northern Hemisphere Climatology

Abstract A modified blocking index is defined based on vertically integrated potential vorticity. The application of this index identifies blocking activity over the Northern Hemisphere during all seasons. The index is developed by systematically identifying the magnitude and spatial scale that best characterizes persistent anticyclonic circulation anomalies in different seasons. By applying a systematic approach to the detection of blocking, the interannual, seasonal, and intraseasonal patterns of blocking frequency across the Northern Hemisphere are able to be characterized. The results are consistent with previous studies in finding that blocking is more frequent in the cold season months than in the warm season, although the results suggest that blocking occurs much more frequently in the summer and fall than many studies have previously reported. By examining blocking frequency monthly, interesting patterns of intraseasonal variability are found, especially over the central Pacific in August and the eastern Pacific in September and October, where blocking is nearly as frequent as in the winter. Possible explanations for this intraseasonal variability are discussed.

Seasonality and site fidelity of the zebra shark, Stegostoma fasciatum, in southeast Queensland, Australia

Site fidelity and migratory movements of vertebrate animals occur at many spatial and temporal scales. Larger migratory movements tend to occur in species that live in seasonal environments in which food supplies vary markedly, while species found in thermally stable environments are more site-attached. In the marine environment, seasonal migrations are often associated with predictable temporary aggregations that have largely been targeted for exploitation. We employed passive acoustic telemetry to investigate inter- and intraseasonal site fidelity of zebra sharks to an aggregation site in southeast Queensland, Australia, close to the southern latitudinal extent of this species' range. We tracked 10 zebra sharks over two aggregation seasons (21 months). We applied a generalized linear mixed-effects model to investigate the presence/absence of these zebra sharks with respect to several environmental variables. We found that different environmental factors were associated with site fidelity of zebra sharks at different temporal levels and that these may be indicative of the mechanisms driving the movements. Seasonal patterns may be driven by endogenous systems, and cues such as photoperiod and water temperature are likely to be important. Intraseasonal patterns are more likely to be indicative of direct behavioural responses to changes in environmental conditions such as increased wave heights, as well as foraging bouts away from a core refuge. Understanding the relative contributions of these environmental parameters, as well as biological factors, will be important for making predictions of site fidelity and movements of migratory marine vertebrates under differing future scenarios such as increases in sea temperature.

An Evaluation Metric for Intraseasonal Variability and its Application to CMIP3 Twentieth-Century Simulations

The intraseasonal variability (ISV) is an intermittent phenomenon with variable perturbation patterns. To assess the robustness of the simulated ISV in climate models, it is thus interesting to consider the distribution of perturbation patterns rather than only one average pattern. To inspect this distribution, the authors first introduce a distance that measures the similarity between two patterns. The reproducibility (realism) of the simulated intraseasonal patterns is then defined as the distribution of distances between each pattern and the average simulated (observed) pattern. A good reproducibility is required to analyze the physical source of the simulated disturbances. The realism distribution is required to estimate the proportion of simulated events that have a perturbation pattern similar to observed patterns. The median value of this realism distribution is introduced as an ISV metric. The reproducibility and realism distributions are used to evaluate boreal summer ISV of precipitations over the Indian Ocean for 19 phase 3 of the Coupled Model Intercomparison Project (CMIP3) models. The 19 models are classified in increasing ISV metric order. In agreement with previous studies, the four best ISV metrics are obtained for models having a convective closure totally or partly based on the moisture convergence. Models with high metric values (poorly realistic) tend to give (i) poorly reproducible intraseasonal patterns, (ii) rainfall perturbations poorly organized at large scales, (iii) small day-to-day variability with overly red temporal spectra, and (iv) less accurate summer monsoon rainfall distribution. This confirms that the ISV is an important link in the seamless system that connects weather and climate.

An Evaluation Metric for Intraseasonal Variability and its Application to CMIP3 Twentieth-Century Simulations

AbstractThe intraseasonal variability (ISV) is an intermittent phenomenon with variable perturbation patterns. To assess the robustness of the simulated ISV in climate models, it is thus interesting to consider the distribution of perturbation patterns rather than only one average pattern. To inspect this distribution, the authors first introduce a distance that measures the similarity between two patterns. The reproducibility (realism) of the simulated intraseasonal patterns is then defined as the distribution of distances between each pattern and the average simulated (observed) pattern. A good reproducibility is required to analyze the physical source of the simulated disturbances. The realism distribution is required to estimate the proportion of simulated events that have a perturbation pattern similar to observed patterns. The median value of this realism distribution is introduced as an ISV metric. The reproducibility and realism distributions are used to evaluate boreal summer ISV of precipitations over the Indian Ocean for 19 phase 3 of the Coupled Model Intercomparison Project (CMIP3) models. The 19 models are classified in increasing ISV metric order. In agreement with previous studies, the four best ISV metrics are obtained for models having a convective closure totally or partly based on the moisture convergence. Models with high metric values (poorly realistic) tend to give (i) poorly reproducible intraseasonal patterns, (ii) rainfall perturbations poorly organized at large scales, (iii) small day-to-day variability with overly red temporal spectra, and (iv) less accurate summer monsoon rainfall distribution. This confirms that the ISV is an important link in the seamless system that connects weather and climate.

Intraseasonal patterns in shorebird nest survival are related to nest age and defence behaviour

Nest survival may vary throughout the breeding season for many bird species, and the nature of this temporal variation can reveal the links between birds, their predators, and other components of the ecosystem. We used program Mark to model patterns in nest survival within the breeding season for shorebirds nesting on arctic tundra. From 2000 to 2007, we monitored 521 nests of five shorebird species and found strong evidence for variation in nest survival within a nesting season. Daily nest survival was lowest in the mid-season in 5 of 8 years, but the timing and magnitude of the lows varied. We found no evidence that this quadratic time effect was driven by seasonal changes in weather or the abundance of predators. Contrary to our prediction, the risk of predation was not greatest when the number of active shorebird nests was highest. Although nest abundance reached a maximum near the middle of the breeding season, a daily index of shorebird nest activity was not supported as a predictor of nest survival in the models. Predators' access to other diet items, in addition to shorebird nests, may instead determine the temporal patterns of nest predation. Nest survival also displayed a positive, linear relationship with nest age; however, this effect was most pronounced among species with biparental incubation. Among biparental species, parents defended older nests with greater intensity. We did not detect a similar relationship among uniparental species, and conclude that the stronger relationship between nest age and both nest defence and nest survival for biparental species reflects that their nest defence is more effective.

Stress hormones suggest opposite trends of food availability for planktivorous and piscivorous seabirds in 2 years

Apex predators can provide valuable information about effects of climate variability on trophodynamics in the Bering Sea. We used corticosterone (the primary avian stress hormone, “CORT”) as a proxy of changes in prey availability for planktivorous and piscivorous seabirds. CORT secretion reflects energy balance in breeding individuals and can be used to monitor changes in the marine environment that alter food availability. We tested whether CORT in planktivorous least auklets (Aethia pusilla) and piscivorous thick-billed murres (Uria lomvia) on two Pribilof Islands differed spatially or temporally in 2003 and 2004. During June–September of each year, we sampled birds breeding on St. Paul and St. George Islands. We found that seasonal dynamics of CORT varied between years. Although the seasonal dynamics were similar between islands in a year, in 2004 there were inter-island differences in CORT levels for both species. In 2003, CORT in murres was low throughout the season, suggesting that their prey availability (primarily forage fishes) was consistently good. In 2004, CORT levels suggested that overall food availability was poor for murres and declined as the season progressed. For auklets, inter-annual variability was associated with contrasting intra-seasonal patterns in the availability of zooplankton prey (primarily Neocalanus spp.). In 2003, high early-season (June) CORT indicated that auklets were food-limited, but CORT decreased in July, suggesting that the availability of zooplankton improved as the season progressed. In 2004, CORT was low early in the season (June), but an abrupt increase late in the season (July) suggests that food became scarce. Our data indicate that environmental differences between 2003 and 2004 affected prey availability for planktivorous and piscivorous alcids in opposite ways. These results suggest that in the shelf regions of the Bering Sea, the populations of apex predators feeding on zooplankton may be affected by environmental fluctuations differently than those feeding on forage fish.

Rubbish, Routines, and Practice: Chipped Stone Blades from Uruk-Period Sharafabad, Iran

Through the analysis of chipped stone blades from Uruk-period Sharafabad (Khuzestan), this paper examines routines and practices of villagers faced with agricultural uncertainty and state demands. Annual, seasonal and intra-seasonal patterns of tool production, use and discard, along with evidence for various domestic pursuits, show that villagers maintained elements of their daily lives in the face of poor crop yields but altered both types and intensities of production activities in order to do so. The results demonstrate the possibilities of archaeological analyses at very line temporal scales, while at the same time illustrating some methodological and interpretive challenges posed by such research.