Moho Depth of Northern Baja California, Mexico, From Teleseismic Receiver Functions

We estimated Moho depths from data recorded by permanent and temporary broadband seismic stations deployed in northern Baja California, Mexico, using the receiver function technique. This region is composed of two subregions of contrasting geological and topographical characteristics: The Peninsular Ranges of Baja California (PRBC), a batholith with high elevations (up to 2600 m); and the Mexicali Valley (MV) region, a sedimentary environment close to sea level. Crustal thickness derived from the P‐to‐S converted phases at 29 seismic stations were analyzed in 3 profiles: two that cross the two subregions, in ∼W‐E direction, and the third one that runs over the PRBC in a N‐S direction. For the PRBC, Moho depths vary from 35 to 45‐km, from 33ºN to 32ºN; and from 30 to 46‐km depth from 32ºN to 30.5ºN. From a profile that crosses the subregions in the W‐E direction; Moho depths vary from 45 to ∼34‐km under western and eastern PRBC, respectively; with an abrupt change of depth under the Main Gulf Escarpment (30º), from ∼32 to 30‐km; and depths of 17‐20‐km under the MV. Moho depths of the profile in an ∼W‐E direction at ∼31.5ºN from ∼30 to 40‐km, under topography that increase from 0 to 2600 m; and became shallower (16‐km depth) as the profile reaches the Gulf of California. These results show that deeper Moho is related to higher elevations with an abrupt change under the Main Gulf Escarpment, except for western PRBC were the Moho depth is not simply reflect isostatic compensation

Moho Depth of Northern Baja California, Mexico, From Teleseismic Receiver Functions

We estimated Moho depth from data recorded by permanent and temporary broadband seismic stations deployed in northern Baja California, Mexico using the receiver function technique. This region is composed, mainly, of two subregions of contrasting geological and topographical characteristics: The Peninsular Ranges of Baja California (PRBC), a batholith with high elevations (up to 2600 m above mean sea level); and the Mexicali Valley (MV) region, a sedimentary environment at around the mean sea level. Crustal thickness derived from the P-to-S converted phases at 29 seismic stations were analyzed in 3 profiles: two that cross the two subregions, in a ~W-E direction, and the third one that runs over the PRBC in a N-S direction. For the PRBC region, Moho depths vary from 35 to 45 km, from 33°;N to 32°;N; and from 30 to 46 km depth from 32°;N to 30.5°;N. From a profile that crosses the subregions in the W-E direction; Moho depths vary from 45 to ~34 km under the PRBC; with an abrupt change of depth under the Main Gulf Escarpment, from ~32 to 30 km; and depths of 17-20 km under the MV region. Moho depths of the profile that runs, of an almost W-E direction at ~31.5°; N, follow the eltimetry from 0 to 2600 m: from ~30 to 40 km; and became shallower (16 km depth) as the profile reaches the Gulf of California. These results show that deeper Moho is related to higher elevations with an abrupt change under the Main Gulf Escarpment

Farms of the future guidelines

The farms of the future (FOTF) approach is an interactive climate adaptation, knowledge sharing and learning experience that transforms climate forecasts into field-based realities by physically taking participants on a journey to areas that already experience climatic conditions that represent plausible future climate scenarios. The hypothesis behind this is that the knowledge exchange process can enhance a farmer’s/village’s capacity to adapt to changing climatic conditions by exposing them to innovative farming communities that have already successfully adapted their agricultural practices to various distinct climatic conditions the reference village might experience

Climate change favors rice production at higher elevations in Colombia

Rice (Oriza sativa) feeds nearly half of the world’s population. Regional and national studies in Asia suggest that rice production will suffer under climate change, but researchers conducted few studies for other parts of the world. This research identifies suitable areas for cultivating irrigated rice in Colombia under current climates and for the 2050s, according to the Representative Concentration Pathway (RCP) 8.5 scenario. The methodology uses known locations of the crop, environmental variables, and maximum entropy and probabilistic methods to develop niche-based models for estimating the potential geographic distribution of irrigated rice. Results indicate that future climate change in Colombia could reduce the area that is suitable for rice production by 60%, from 4.4 to 1.8 million hectares. Low-lying rice production regions could be the most susceptible to changing environmental conditions, while mid-altitude valleys could see improvements in rice-growing conditions. In contrast to a country like China where rice production can move to higher latitudes, rice adaptation in tropical Colombia will favor higher elevations. These results suggest adaptation strategies for the Colombian rice sector. Farmers can adopt climate-resilient varieties or change water and agronomic management practices, or both. Other farmers may consider abandoning rice production for some other crop or activity

Seasonal abundance of Diaphorina citri (Hemiptera: Liviidae) in citrus groves in Cazones, Veracruz, México

Se evaluó la abundancia estacional del Psílido Asiático de los Cítricos Diaphorina citri Kuwayama, en plantaciones de cítricos en la región de Cazones, Veracruz, México. Durante el período de Febrero de 2010 a Febrero de 2012 se realizaron registros quincenales de adultos de D. citri en trampas amarillas, así como la presencia de huevos, ninfas, adultos y enemigos  naturales en los brotes. Las poblaciones del psílido se presentaron durante todo el periodo de estudio, detectando picos poblacionales en Febrero, Marzo, Abril y Julio en las plantaciones. Los incrementos en las infestaciones del psílido mostraron una relación positiva con respecto a la abundancia de brotes, y éstos a su vez, con latemperatura y precipitación. Durante el periodo de estudio, los enemigos naturales no fueron un factor determinante en la regulación de las poblaciones del psílido, mientras que la abundancia de brotes en los árboles de cítricos, representa un factor clave en el manejo integrado de esta plaga.Seasonal abundance of the Asian Citrus Psyllid, Diaphorina citri Kuwayama, wasevaluated on citrus groves in the region of Cazones, Veracruz, Mexico. For the period from February 2010 to February 2012, biweekly records for adult specimens were made using yellow sticky cardboard traps, as well as the presence of eggs, nymphs, adults, and natural enemies on the flush shoots were also registered. Psyllid populations occurred throughout the period of study, detecting population peaks on February, March, April and July in the citrus plantations. Increases of psyllid infestations were positively related to the abundance of new shoot flushes, and these in turn, were related to the temperature and rainfall. Natural enemies were not a decisive factor in regulating liviid populations, while the abundance of shoot flushes produced by citrus treescould play an important role in integrated psyllid management

Application of CE QUAL-W2 Model: An Approach to the Thermal Structure in the Miguel Martínez Isaza reservoir, Concordia, Antioquia, Colombia

La modelación de la temperatura contribuye a la gestión de embalses, ya que es posible crear escenarios con diferentes condiciones para predecir su respuesta ante los cambios climáticos y los procesos de mezcla. Con este trabajo se busca aportar elementos de análisis del funcionamiento e identificación de los forzantes que dominan la dinámica térmica de un embalse tropical de montaña. Se registró la temperatura y el nivel de agua en tres sitios del embalse durante tres muestreos. Además, se midieron los caudales de entrada y salida al embalse y se analizaron los registros climáticos históricos. Con esta información se construyeron los archivos de entrada del modelo bidimensional CE QUAL-W2, para simular cuatro escenarios climáticos (seco, lluvia, transición y el fenómeno El Niño). De las afluencias se evidenció que la quebrada Santa Mónica en términos hidrodinámicos ejerce su efecto hasta el sitio de captación; de otro lado, la quebrada la Nitrera presenta recirculaciones verticales que aumentan el tiempo de residencia lo que tiene consecuencias en la calidad del agua para este sector del embalse. Los resultados de este ejercicio preliminar de modelación indican que el comportamiento térmico del embalse responde de manera diferenciada según el escenario climático y la magnitud de las extracciones. Durante el fenómeno El Niño y ante un incremento del agua captada, el embalse disminuye el nivel de agua en cerca de un metro y aumenta su temperatura alrededor de 3°C en la zona central del embalse. Ante la tendencia de crecimiento del municipio, se espera mayores demandas de agua que deberán ser suplidas por el embalse, por lo que toman importancia las herramientas de modelación que apoyen la gestión ambiental y reduzcan el riesgo al desabastecimiento ante la vulnerabilidad al cambio de climático.Hydrodynamic modelling of temperature is a tool that contributes to the management of reservoirs because it is possible to create scenarios with different conditions to predict the behavior facing the meteorological changes and the mixing processes. This work seeks to contribute elements of analysis to the functioning and identification of the external factors that dominate the thermal dynamics of a tropical reservoir of mountain. The temperature and the water level were registered in three places of the reservoir, during three campaigns of sampling. In addition, we measured the inflows and outflows to the reservoir and analyzed the climatic historical records. With this information the two-dimensional model CE QUAL-W2 archives was build, in order to simulate 3 climatic periods (dry, transition and wet) and one where El Niño is included. It is clearly demonstrated that Santa Mónica creek has a greater influence in the water extraction. The external factors like the increase of the water extraction and the climatic scenarios influence the temperature and availability of the reservoir, being El Niño scenario the most critical, where the reservoir approximately increases its temperature 3°C and the level of the water diminishes a meter. The reservoir is increasingly susceptible to the shortage of supplies and the decrease of quality in the scenes of drought with the increase of the resource demand. The model is a useful management tool of the reservoir for the future scenarios of climate change

Impact of climate change on African agriculture: focus on pests and diseases

According to the IPCC’s Fifth Assessment Report, changes in the climate over the last 30 years have already reduced global agricultural production by 1 – 5 % per decade relative to a baseline without climate change. In addition, recent studies indicate that even a 2 degrees increase in global temperature will affect agricultural productivity, particularly in the tropics, and this impact will rise with increases in temperature. In this context, this Info Note presents recent evidence on the implications for crops, livestock, and fisheries production, and their associated pests and diseases in Africa