Large-scale emergence of regional changes in year-to-year temperature variability by the end of the 21st century

Global warming is expected to not only impact mean temperatures but also temperature variability, substantially altering climate extremes. Here we show that human-caused changes in internal year-to-year temperature variability are expected to emerge from the unforced range by the end of the 21st century across climate model initial-condition large ensembles forced with a strong global warming scenario. Different simulated changes in globally averaged regional temperature variability between models can be explained by a trade-off between strong increases in variability on tropical land and substantial decreases in high latitudes, both shown by most models. This latitudinal pattern of temperature variability change is consistent with loss of sea ice in high latitudes and changes in vegetation cover in the tropics. Instrumental records are broadly in line with this emerging pattern, but have data gaps in key regions. Paleoclimate proxy reconstructions support the simulated magnitude and distribution of temperature variability. Our findings strengthen the need for urgent mitigation to avoid unprecedented changes in temperature variability.

Optimized Umkehr profile algorithm for ozone trend analyses

The long-term record of Umkehr measurements from four NOAA Dobson spectrophotometers was reprocessed after updates to the instrument calibration procedures. In addition, a new data quality-control tool was developed for the Dobson automation software (WinDobson). This paper presents a comparison of Dobson Umkehr ozone profiles from NOAA ozone network stations (Boulder, OHP, MLO, Lauder) against several satellite records, including Aura Microwave Limb Sounder (MLS; ver. 4.2), and combined SBUV and OMPS records (NASA AGG and NOAA COH). A subset of satellite data is selected to match Dobson Umkehr observations at each station spatially (distance less than 200 km) and temporally (within 24 hours). Umkehr Averaging Kernels (AKs) are applied to vertically smooth all overpass satellite profiles prior to comparisons. The station Umkehr record consists of several instrumental records, which have different optical characterizations, and thus instrument-specific stray light contributes to the data processing errors and creates step changes in the record. This work evaluates the overall quality of Umkehr long-term measurements at NOAA ground-based stations and assesses the impact of the instrumental changes on the stability of the Umkehr ozone profile record. This paper describes a method designed to correct biases and discontinuities in the retrieved Umkehr profile that originate from the Dobson calibration process, repair, or optical realignment of the instrument. The M2GMI and GMI CTM ozone profile model output matched to station location and date of observation is used to evaluate instrumental step changes in the Umkehr record. Homogenization of the Umkehr record and discussion of the apparent stray light error in retrieved ozone profiles are the focus of this paper. Homogenization of ground-based records is of great importance for studies of long-term ozone trends and climate change.

The 6 May 1947 Milwaukee, Wisconsin, Earthquake

The State of Wisconsin is not known for earthquake activity. The authoritative public-facing U.S. Geological Survey Comprehensive Catalog of earthquakes includes only three small (magnitude < 2) earthquakes in the state, all instrumentally recorded. Although other catalogs include more events in Wisconsin, experience has shown that many types of events, such as explosions and cryoseisms, have made their way into earthquake catalogs in this region. In this short report, I summarize available information about an earthquake that was felt in eastern Wisconsin at 15:27 local time on 6 May 1947. As what appears to be the largest historical earthquake in the State of Wisconsin, it is of public interest, its modest size notwithstanding. It appears that no useful instrumental records exist, due in part to a teleseismic event that occurred approximately 3 min later, generating surface waves that were recorded on early long-period instruments in the region. Instrumental data may exist for this event but have not been found. Comparing the felt area with information from recent earthquakes in the region, I estimate an intensity magnitude of 3.8 for the event, with a subjectively estimated uncertainty range 3.5–4.1. Relatively strong effects, including reports of broken dishes in Milwaukee, and shaking described as short but especially sharp, suggest that the event may have been among the sprinkling of shallow earthquakes now known to occur in the upper Great Lakes region.

Rainfall variability in southeast and west-central Africa during the Little Ice Age: do documentary and proxy records agree?

Understanding of long-term climatic change prior to instrumental records necessitates reconstructions from documentary and palaeoclimate archives. In southern Africa, documentary-derived chronologies of nineteenth century rainfall variability and palaeoclimate records have permitted new insights into rainfall variability over past centuries. Rarely considered, however, is the climatic information within early colonial documentary records that emerge from the late fifteenth century onwards. This paper examines evidence for (multi-)seasonal dry and wet events within these earlier written records (c. 1550–1830 CE) from southeast Africa (Mozambique) and west-central Africa (Angola) in conjunction with palaeoclimate records from multiple proxies. Specifically, it aims to understand whether these sources agree in their signals of rainfall variability over a 280-year period covering the ‘main phase’ Little Ice Age (LIA) in southern Africa. The two source types generally, but do not always, show agreement within the two regions. This appears to reflect both the nature of rainfall variability and the context behind documentary recording. Both source types indicate that southeast and west-central Africa were distinct regions of rainfall variability over seasonal and longer timescales during the LIA, with southeast Africa being generally drier and west-central Africa generally wetter. However, the documentary records reveal considerable variability within these mean state climatic conditions, with multi-year droughts a recurrent feature in both regions. An analysis of long-term rainfall links with the El Niño–Southern Oscillation (ENSO) in southeast Africa suggests a complex and possibly non-stationary relationship. Overall, early colonial records provide valuable information for constraining hydroclimate variability where palaeoclimate records remain sparse.

Classification of the flood severity of the Guadalquivir River in the Southwest of the Iberian Peninsula during the 13th to 19th centuries

This study estimates the pluviometric evolution between the 13th and 19th centuries on the southwestern Iberian Peninsula based on the historic records of the impacts of the Guadalquivir River flooding on the city of Seville (Spain). The main documentary source was “Critical history of the floods of the Guadalquivir in Seville”, published in 1878, which compiles news from different observers, who were contemporaries of each event. Regarding the methodology, it was necessary to transfer the information from different documentary sources to ordinal indices, which required developing allocation criteria per flood impact. From the annual assigned flood index, an interannual series was generated. Moreover, for the last decades of the 21st century, quantifying the flooding levels in the records allowed us to relate them directly to instrumental records of rainfall and establish a relationship between these two phenomena. Through interannual weighing of the flooding indices, it was possible to deduce the durations and intensities of sequences of rainy periods between 1250 and 1850. This allowed us to reconstruct the pluviometric evolution. Of the ten floods classified as most destructive during the five centuries analysed, i.e., from 1280 to 1880, five occurred during little more than a century (1598-1701). The obtained results contribute to knowledge on regional rainfall, as well as to historical climatology and hydrology, over multiple centuries.

Theoretical construction of sustainable social awareness in mexican organizations

This article gives an account of the qualitative research process under the Grounded Theory strategy to generate a substantive theoretical construct called Sustainable Social Culture from instrumental records product of an immersion in the field in four industrial units (Martínez, 2020). The first findings raised questions that led to delving into the way in which industrial workers exercise agency and reflexivity in terms of sustainability. This theoretical construct rests on the Sociology of Organizations, Organizational Culture and Environmental Management that contribute to integrating categorical dimensions for their subsequent theorization and conceptual integration whose consistency, internal logic and validity are evidenced.

Pacific contribution to decadal surface temperature trends in the Arctic during the twentieth century

Instrumental records suggest multidecadal variability in Arctic surface temperature throughout the twentieth century. This variability is caused by a combination of external forcing and internal variability, but their relative importance remains unclear. Since the early twentieth century Arctic warming has been linked to decadal variability in the Pacific, we hypothesize that the Pacific could impact decadal temperature trends in the Arctic throughout the twentieth century. To investigate this, we compare two ensembles of historical all-forcing twentieth century simulations with the Norwegian Earth System Model (NorESM): (1) a fully coupled ensemble and (2) an ensemble where momentum flux anomalies from reanalysis are prescribed over the Indo-Pacific Ocean to constrain Pacific sea surface temperature variability. We find that the combined effect of tropical and extratropical Pacific decadal variability can explain up to ~ 50% of the observed decadal surface temperature trends in the Arctic. The Pacific-Arctic connection involves both lower tropospheric horizontal advection and subsidence-induced adiabatic heating, mediated by Aleutian Low variations. This link is detected across the twentieth century, but the response in Arctic surface temperature is moderated by external forcing and surface feedbacks. Our results also indicate that increased ocean heat transport from the Atlantic to the Arctic could have compensated for the impact of a cooling Pacific at the turn of the twenty-first century. These results have implications for understanding the present Arctic warming and future climate variations.

Large-scale climate signals of a European oxygen isotope network from tree rings

We investigate the climate signature of δ18O tree-ring records from sites distributed all over Europe covering the last 400 years. An empirical orthogonal function (EOF) analysis reveals two distinct modes of variability on the basis of the existing δ18O tree-ring records. The first mode is associated with anomaly patterns projecting onto the El Niño–Southern Oscillation (ENSO) and reflects a multi-seasonal climatic signal. The ENSO link is pronounced for the last 130 years, but it is found to be weak over the period from 1600 to 1850, suggesting that the relationship between ENSO and the European climate may not be stable over time. The second mode of δ18O variability, which captures a north–south dipole in the European δ18O tree-ring records, is related to a regional summer atmospheric circulation pattern, revealing a pronounced centre over the North Sea. Locally, the δ18O anomalies associated with this mode show the same (opposite) sign with temperature (precipitation). Based on the oxygen isotopic signature derived from tree rings, we argue that the prevailing large-scale atmospheric circulation patterns and the related teleconnections can be analysed beyond instrumental records.

Multi-Proxy Records of Late Holocene Flood Events From the Lower Reaches of the Narmada River, Western India

Analyses of a fluvial sedimentary sequence from the lower reaches of the Narmada River establish a record of rhythmic cycles of sediment facies that represent floods during the late Holocene. The south-west Indian monsoon strongly influences the study area, and heavy rainfall or cyclones which originate from either the Bay of Bengal or the Arabian Sea, also affect the region. Optically stimulated luminescence dating places the 8 m thick sediment sequence in the climate transition phase which ranges from the Medieval Warm Period to the Little Ice Age. Multi-proxy analyses including high-resolution granulometry, magnetic susceptibility, ferromagnetic mineral concentration, facies major oxide geochemistry, and micro-fossil records (from two sedimentary units) are used to study these late Holocene flood events. The latter are characterised by multiple sediment facies, depositional events, changes in channel morphology, and distinctive flood signatures. Integration of these records enables to identify two distinct aggradations viz. phase I and phase II, as well as a relative change in channel morphology. The study describes 11 flooding events and their imprints over multi-proxy records. Historic documents and instrumental records from the town of Bharuch referring to floods, movement of channel sand, channel shallowing, and the dysfunction of the ancient port of Bharuch further validate the inferences drawn from the sedimentary sequence. The study exemplifies the need to use high resolution and multi-proxy studies to interpret paleoflood records and climate signatures in order to build archives of monsoonal rivers.

Influence of past vegetation changes on estimates of ground surface temperature histories GSTH obtained by inversion of borehole temperature logs: Example from the Western Canadian Sedimentary Basin

Functional space inversions (FSI) of precise temperature logs from 43 wells, located in low conductivity clastic sediments of the Western Canadian Sedimentary Basin, (WCSB), reveal evidence of extensive, recent ground surface temperature (GST) warming. Simultaneous inversion of log data acquired during the period of 1987-2005, as well as averaging of the individual site reconstructions of subsurface temperature signals, indicate evidence of high magnitude of warming of about 2°C (with standard deviations of 0.7°C). Magnitudes of such warning events exceeds 3-4 times that of globally averaged continental GST’s for the 20th century and is significantly higher than that of changes in surface air temperatures (SAT) based on instrumental records in the WCSB. Within this region, GST warming in the 20th century could have been at least partially caused by changes in vegetation cover. The temporary or permanent removal of vegetation, through deforestation, forest fires, and grassland conversion for agriculture occurred in the relatively young provinces of WCSB, during centennial long settlement and development programs. This might have significantly changed the surface properties of the area, since changes in surface albedo affects the radiation budget, while changes in the thermal, moisture and aerodynamic characteristics affect the energy balance. The results of our modelling for typical range of bedrock thermal diffusivities and assumed surface warming history for studied areas in WCSB show that a possible jump in ground surface temperature can easily be interpreted in the FSI results as a gradual warming event of large amplitude and attributed to SAT.