The lack of previous exposure to arbovirus and the ongoing geographical expansion of viable vector populations has fostered the implementation of preventive strategies in those areas more prone to ...disease importation. Catalonia receives a wealth of travelers from Southeast Asia, South America and the Caribbean and around 700 cases of imported arbovirosis (2012–2016, totaling dengue, chikungunya, and Zika), have been notified in primary care health centers, traveler advice public health services and main hospitals. With the large asymptomatic proportion of infections well-known for these diseases, the threat for autochthonous outbreaks increases in those areas that, for particular environmental and socio-demographic conditions, might be more susceptible. Operational early-warning systems are lacking in most places where these outbreaks pose a serious health treat.
Here we present the ARBOCAT platform for the prediction of autochthonous outbreaks of arboviruses emanating from imported cases, implemented for Catalonia at municipality resolution. Three sub-models provide estimations for importation rates and the basic reproduction number and their outcomes are used to fit a stochastic compartmental model that yields the generation time and the risk of local outbreaks for 948 municipalities. We used also ISIMIP-2b (The Inter-Sectoral Impact Model Intercomparison Project) temperature data to generate future outbreak risk maps for the RCP 2.6 and RCP 8.5 scenarios (where RCP is Representative Concentration Trajectories).
Substantial differences exist between the low and middle-risk scenarios but most Catalonia municipalities are not at risk for a sustained epidemic. Instead, high R0 are obtained for the maximum risk scenario, with the number of municipalities affected being over 150. In the RCP 8.5 scenario, many of the highest risk areas lie in the most populated cities in the coastal region, particularly in the south near to the Ebre’s river.
The current outbreak risk is low, both for the mean and minimum temperature scenarios and rises in the high-risk situation. Projections for 2050 are not so optimistic, leading to a significant increase in affected municipalities, over 100, mainly in the coastal area due to the temperature increase followed in RCP 8.5.
This study was partially supported by the Catalonia Department of Health and the Spanish Ministry of Science and Innovation.
•ARBOCAT is a prediction tool for arboviral outbreaks in Catalonia Spain.•The Platform is composed of three probabilistic sub-models.•The spatial resolution is at the municipality level.•The platform provides risk indices for climate change scenarios.•We analyze several climate change scenarios using ISIMIP2b models.
Predicting endemic cholera Pascual, M.; Chaves, L. F.; Cash, B. ...
Climate research,
04/2008, Letnik:
36, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Retrospective studies of cholera time series in Bangladesh have established a role of the El Niño Southern Oscillation (ENSO), but also of the non-linear dynamics of the disease itself, through ...changes in the population levels of immunity in this endemic region. The prediction ability of a semi-mechanistic time series model that incorporates both these elements is examined. Results show that ENSO is a key covariate and confirm the importance of its interplay with immunity levels, now from the perspective of prediction. They support the feasibility of using the model as a forecasting tool: the lack of extreme events between 2001 and 2005 would have been anticipated with 75% confidence half a year ahead with a model fitted to data up to 2000. Long-term change in the transmission rate, the non-mechanistic part of the model, sets limits to the forecasting horizon because of a breakdown in its relationship with river discharge towards the end of the 1990s. We discuss this and other limitations of the approach as well as future directions related to the development of an early warning system for cholera in this region.
Cholera Dynamics and El Niño-Southern Oscillation Pascual, Mercedes; Rodó, Xavier; Ellner, Stephen P. ...
Science (American Association for the Advancement of Science),
09/2000, Letnik:
289, Številka:
5485
Journal Article
Recenzirano
Analysis of a monthly 18-year cholera time series from Bangladesh shows that the temporal variability of cholera exhibits an interannual component at the dominant frequency of El Niño-Southern ...Oscillation (ENSO). Results from nonlinear time series analysis support a role for both ENSO and previous disease levels in the dynamics of cholera. Cholera patterns are linked to the previously described changes in the atmospheric circulation of south Asia and, consistent with these changes, to regional temperature anomalies.
The incidence of malaria in the East African highlands has increased since the end of the 1970s. The role of climate change in the exacerbation of the disease has been controversial, and the specific ...influence of rising temperature (warming) has been highly debated following a previous study reporting no evidence to support a trend in temperature. We revisit this result using the same temperature data, now updated to the present from 1950 to 2002 for four high-altitude sites in East Africa where malaria has become a serious public health problem. With both nonparametric and parametric statistical analyses, we find evidence for a significant warming trend at all sites. To assess the biological significance of this trend, we drive a dynamical model for the population dynamics of the mosquito vector with the temperature time series and the corresponding detrended versions. This approach suggests that the observed temperature changes would be significantly amplified by the mosquito population dynamics with a difference in the biological response at least 1 order of magnitude larger than that in the environmental variable. Our results emphasize the importance of considering not just the statistical significance of climate trends but also their biological implications with dynamical models.
In this study the differences in the measured atmospheric CO2 mixing ratio at three aircraft profiling sites in NE Spain separated by 60 km are analyzed in regard to the variability of the surface ...fluxes in the regional surface influence area. First, the Regional Potential Surface Influence (RPSI) for fifty-one days in 2006 is calculated to assess the vertical, horizontal and temporal extent of the surface influence for the three sites at the regional scale (104 km2 ) at different altitudes of the profile (600, 1200, 2500 and 4000 meters above the sea level, m a.s.l.). Second, three flights carried out in 2006 (7 February, 24 August and 29 November) following the Crown Atmospheric Sampling (CAS) design are presented to study the relation between the measured CO2 variability and the Potential Surface Influence (PSI) and RPSI concepts. At 600 and 1200 m a.s.l. the regional signal is confined up to 50 h before the measurements whereas at higher altitudes (2500 and 4000 m a.s.l.) the regional surface influence is only recovered during spring and summer months. The RPSI from sites separated by 60 km overlap by up to 70% of the regional surface influence at 600 and 1200 m a.s.l., while the overlap decreases to 10-40% at higher altitudes (2500 and 4000 m a.s.l.). The scale of the RPSI area is suitable to understand the differences in the measured CO2 concentration in the three vertices of the CAS, as CO2 differences are attributed to local surrounding fluxes (February) or to the variability of regional surface influence as for the August and November flights. For these two flights, the variability in the regional scale influences the variability measured in the local scale. The CAS sampling design for aircraft measurements appears to be a suitable method to cope with the variability of a typical grid for inversion models as measurements are intensified within the PBL and the background concentration is measured every ~102 km.
The Indian summer monsoon rainfall (ISMR) over the Western Ghats (WG) and the Bay of Bengal (BoB) is marked by the intraseasonal oscillations (ISOs) with preferred 10–20-day and 30–50-day bands. On ...the basis of pentad Climate Prediction Center Merged Analysis Precipitation and daily sea level pressure and winds at 850 hPa derived from European Center for Medium-range Weather Forecast reanalysis, we present the structure and evolution of the ISOs linked to the ISMR variations over the WG and the BoB and the associated anomalies of the atmospheric circulation using the approaches of wavelet analysis, bandpass filtering and composite analysis. This study reveals that the activities of both the intertropical convergence zone (ITCZ) and the western Pacific subtropical high (WPSH) contribute strongly to the structure and propagation of the ISOs on intraseasonal time scales. Northward development and propagation of the ITCZ plays a critical role in the northward-propagating ISOs, but not in the westward-propagating BoB 10–20-day ISOs. The latter ISOs may be linked, instead, to the activity of synoptic-scale weather systems to the east over the western tropical Pacific. The enhanced ITCZ in the tropical Indian Ocean plays a strong role in the sudden strengthening of the WPSH during the transition from the break to active phase of the 30–50-day ISOs. We find that the strong WPSH in the Asian summer monsoon season, with generally northward advance and eastward withdrawal, promotes the formation of a northwest to southeast tilted anomalous rainfall belt over the East Asian tropical summer monsoon region and the western tropical Pacific in the 30–50-day low-frequency band. Positive (Negative) elongated rainfall anomalies with an unbroken northwest-southeast tilt, strong easterly (westerly) anomalies in the tropical Pacific, and northward advance and eastward movement of strong (weak) WPSH are favorable for maintaining the eastward propagation of the 30–50-day ISOs in the Pacific. Daily high-resolution sea surface temperature obtained from the National Oceanic and Atmospheric Administration is used to explain the propagation features of the 10–20-day ISOs in the Indian Ocean.
Vertical distribution of atmospheric CO2 mixing ratios, as well as CO2 vertical variance and gradient are related to the vertical stability at the time of measurement, to the transport of coherent ...upstream plumes studied through changes in the upstream surface influence or to the historic mixing processes and dispersive behavior. Three vertical profiles of CO2 mixing ratios measured from 900 to 4200 m above sea level (masl) in 2006 at La Muela, Spain (LMU, 41.60°N 1.10°W, 570 masl) are examined. Changes in CO2 mixing ratio are associated with changes of the atmospheric physical parameters on the day of the survey; and with the transport of coherent air masses. Its consistency is examined through changes of the historical horizontal dispersion and chaotic mixing dynamics of air masses during the four days prior to measurements. A climatology of Lagrangian backward simulations run once a week at four altitudes (600, 1200, 2500 and 4000 masl) at LMU for 2006 shows that dispersion in these altitudes is superdiffusive (exponent coefficient γ > 1/2) and mixing follows a chaotic dynamics (power law exponent λ > 0) at all altitudes and in all seasons. Furthermore, a Horizontal Mixing Discontinuity (HMD) at ∼2500 masl separates two layers with different constraints on vertical mixing. Above the HMD, more coherent air masses and laminar transport characterizes the dynamics of atmospheric horizontal mixing whereas below it, filamentation and chaotic mixing dominate horizontal mixing. In the lower part of the vertical profile, within the ABL, mixing takes place by convection. Chaotic mixing below the HMD induces the boundary layer entrainment. Results highlight that there are two main discontinuities in the air column which separates different atmospheric dynamics. The ABL is driven by local meteorological conditions of the site at the sampling time; the HMD is driven by the synoptic‐scale historical mixing conditions of air masses. The effect of horizontal transport in the free troposphere should be considered equally as important as the local vertical mixing processes in the atmospheric boundary layer when interpreting CO2 vertical gradients. The dispersive exponents can be used to identify the transport of coherent plumes from anthropogenic emissions with different carbon composition that the one‐single backtrajectories models do not detect.
Analysis of data from seventeen rainfall stations in the Iberian Peninsula, Balearic Islands and Northern Africa has revealed significant El Nino-Southern Oscillation (ENSO) signals in Europe. Both ...North Atlantic Oscillation (NAO) and Southern Oscillation (SO) exert an influence on Iberian climate, but at different temporal and spatial scales. Though most of the peninsula is under NAO influence in winter, some stations in the eastern region show no connection with this phenomenon. The same is found for ENSO, with a positively correlated region appearing in the eastern part of Spain, while the rest of the peninsula remains insensitive. The correlation between ENSO and Iberian rainfall has increased towards the end of the present century, with strong positive signals spanning over half of the area studied. The percentage of springtime variability due to ENSO has similarly increased, reaching up to 50% in certain areas. We also show how there are outstanding climatic sensors of these phenomena such as Lake Gallocanta, which manifests a positive response to ENSO while appears insensitive to NAO. Common long-term patterns are observed between SOI and an inferred lake level series, suggesting a constant influence of the low-frequency component of ENSO throughout the period considered. Lake drying phases every 14 years reflect the impact of this signal, approximately every four ENSO events.
The new “Crown” aircraft sampling (CAS) approach integrates CO2 data obtained through horizontal transects and vertical profiles, sampling a specific volume of air at different atmospheric sections: ...600 m, 1200 m, and 2500 m above the sea level (masl). This approach provides new tools to model fluxes in relation with meteorological conditions. It has been applied over a plain in the basin of the river called Ebre in the North East of Spain, with a triangular section defined by Linyola, Mequinensa's dam and Binèfar, taking up 1500 km2. The main human activity is agriculture, either irrigated or dry land. Horizontal transects at 600 and 1200 masl were sampled for CO2, with vertical profiles at the vertexes from 600 to 2500 masl (ground level is around 400 masl). The three‐dimensional configuration of the CAS Design enables the study of the CO2 fluxes between sections. Data have been obtained on a monthly basis since February 2006 until nowadays. In order to study the influence of forced turbulence in the atmospheric CO2 spatial distribution, two data sets are examined: the flight of 7 February 2006, performed under stable anticyclonic weather conditions; and the 6 March 2006 flight, characterized by strong northerly winds. The presence of stable/unstable layers in the February flight resulted in a stepwise vertical distribution of CO2 (with an increase from the free troposphere, 383 ppmv, to 400 ppmv close to the ground) whereas the unstable low troposphere sampled in March 2006 provided flat CO2 vertical profiles (concentrations ranging from 385 to 387 ppmv). In regard to the variability in the horizontal sections, the calculation of the Hurst exponents (H) provides a way to measure the persistence of vertical transport along the horizontal transects. In the February flight, CO2 concentration in transects shows the imprint of a spreading vertical transport from land (H > 0.90) but it is partially wiped away by high turbulence levels in the March flight (H = 0.79). From these results we expect CAS Design to provide better estimates of CO2 fluxes in the future.
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