Inland sanctuaries of water vapour for atmospheric circulation. (by Diego Fdez-Sevilla)
Since bodies of water are active features involved in feeding the atmospheric circulation adding water vapour, I have been wondering for some time already about the grade of impact that atmospheric circulation could suffer when the availability of water resources inland are strongly modified due to compartmentalization, relocation or even from disappearing.
Are you aware of any study looking at such possibility? Here I share a pick on what I am finding out on the disturbance of atmospheric circulation from alterations over inland water sources and processes involved. Feel free to make suggestions and/or comments in order to extend the coverage in this issue.
Source: NASA Earth Observatory
Green and tan shades show the extent of the water in Lake Urmia (also Orumiyeh or Orumieh) in western Iran. The lake is highly saline and only a few tens of meters deep even at high water. The shoreline appears as a white margin of salt. The lake is one of the largest in the Middle East, measuring 130 kilometers (80 miles) from the northern shoreline to the vegetated delta.
Rivers that flow into the lake appear as narrow green lines, especially on the southeastern lake margin (image top right). These rivers form deltas marked by clusters of green agricultural fields; soft soils and the nearby water supply support farming in an otherwise dry region. The lake and its wetlands have been declared a UNESCOBiosphere Reserve.
The city of Urmia stands out as a distinct gray patch surrounded by fields. On the opposite shore, an extinct volcano appears as an oval shape. A causeway and bridge connect the shorelines at this point.
The lake has been experiencing a drastic loss of water and now holds only 5 percent of its known high-stage volume. The drying is vividly illustrated by the fact that the volcano used to be entirely surrounded by the lake. The drop in water levels is related to a long-term decrease in rainfall and the extraction of water for farming. The progressive drying of the lake since 1984 is shown in this sequence of still images.
Astronaut photograph ISS040-E-17264 was acquired on June 23, 2014, with a Nikon D3S digital camera using an 80 millimeter lens, and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by the Expedition 40 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Programsupports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by M. Justin Wilkinson, Jacobs at NASA-JSC.
The following article studies water cycles and patterns in the spatial precipitation. (2010) “Atmospheric circulation is reflected in precipitation isotope gradients over the conterminous United States”
During the winter, southward displacement of the jet stream and establishment of high pressure over the continental interior lead to increased dominance of moist Pacific air masses across the western United States. Anticyclonic flow around continental high‐pressure systems brings dry Arctic air masses deep into the middle of the continental United States, producing frontal storm systems that severely limit the propagation of Gulf of Mexico and Atlantic moisture into the continental interior [Maglaras et al., 1995]. During both seasons, secondary vapor sources such as continental evapotranspiration [e.g., Ingraham and Taylor, 1991] and evaporation from the Great Lakes [Gat et al., 1994; Niziol et al., 1995; Burnett et al., 2004] contribute additional moisture within some regions. …
- The recognition that circulation and vapor‐source patterns are reflected in precipitation isotope gradient fields at continental scales presents a number of opportunities for studying the modern atmospheric and land‐atmosphere components of the water cycle. Water vapor transport and mixing have been modeled extensively but are extremely difficult to verify observationally. Moreover, there is significant concern that anthropogenic land use change and climate change are significantly modifying these processes [e.g., Betts et al., 2007; Zhang et al., 2007]. Recent advances in technology promise to enable routine regional‐ to continental‐scale monitoring of atmospheric water vapor isotopic composition from satellite and ground‐based platforms within the next decade [Helliker and Noone, 2010]. The spatial gradient analysis proposed here represents a simple method that could be applied to the resultant data to derive first‐order information about atmospheric and landatmosphere moisture fluxes and test models for these processes, and could easily be adopted as a routine data analysis method in atmospheric and precipitation isotope monitoring efforts.
- Within the paleoclimate field, isotope archive records from individual sites have been widely useful in reconstructing time series for local paleoclimate variables, but in order to better understand past climate and the relationships between climate dynamics and climate change impacts, researchers need to be able to reconstruct synoptic and dynamic features of climate that are defined by their spatial structure [e.g., Shinker et al., 2006]. Such reconstructions may be obtained from single‐site records where relationships between local climate and large‐scale features are especially robust, but a less ambiguous approach would involve direct reconstruction of the spatial patterns themselves. This study demonstrates relationships between the spatial structure of precipitation isotopes and aspects of the modern atmospheric circulation over the contiguous United States. Our work suggests that changes in these features of the synoptic circulation, and in likelihood other similar features occurring elsewhere in the world, could be directly reconstructed based on spatially distributed networks of isotope archive records. Until recently the recovery of archive records required to support interpretations based on spatial analysis has been prohibitive, but advances in analytical methodology and recent examples from lacustrine and tree ring research suggest that this may no longer be the case [e.g., Feng et al., 2007]. If so, spatial analysis of isotope archive data may produce new, more direct records of past atmospheric circulation and large‐scale climate features, supporting an improved understanding of past climate states and climate change impacts.
The following article studies Terrestrial water fluxes.
Abstract. “Renewable fresh water over continents has input from precipitation and losses to the atmosphere through evaporation and transpiration. Global-scale estimates of transpiration from climate models are poorly constrained owing to large uncertainties in stomatal conductance and the lack of catchment-scale measurements required for model calibration, resulting in a range of predictions spanning 20 to 65 per cent of total terrestrial evapotranspiration (14,000 to 41,000 km3 per year) (refs 1–5). Here we use the distinct isotope effects of transpiration and evaporation to show that transpiration is by far the largest water flux from Earth’s continents, representing 80 to 90 per cent of terrestrial evapotranspiration. On the basis of our analysis of a global data set of large lakes and rivers, we conclude that transpiration recycles 62,000±8,000 km3 of water per year to the atmosphere, using half of all solar energy absorbed by land surfaces in the process. We also calculate CO2 uptake by terrestrial vegetation by connecting transpiration losses to carbon assimilation using water-use efficiency ratios of plants, and show the global gross primary productivity to be 129632 gigatonnes of carbon per year, which agrees, within the uncertainty, with previous estimates. The dominance of transpiration water fluxes in continental evapotranspiration suggests that, from the point of view of water resource forecasting, climate model development should prioritize improvements in simulations of biological fluxes rather than physical (evaporation) fluxes.”
(2013) Impact of climate warming on European inland waters. Martin T. Dokulil
Institute for Limnology, Mondsee, Austria.
Climate change impacts include such an overwhelming number of facets that the extent of references is impossible to cover. The selection presented in this review on global warming is presumably subjective, although the author has tried to assemble relevant and/or most recent information. The references specified should be regarded as examples that direct the reader to more information on a specific subject.
Limited access due to copyright restrictions.
- Vegetation influences rainfall patterns more than is generally recognised.
- Recent findings imply a major role of forest cover in maintaining rainfall.
- Atmospheric moisture flows, condensation, and winds are all vulnerable to forest loss.
- Plant sciences must have a greater role in understanding and safeguarding our climate.
Most life on land depends on water from rain, but much of the rain on land may also depend on life. Recent studies indicate that vegetation, especially tree cover, influences rain and rainfall patterns to a greater extent than is generally assumed. Here, I briefly highlight some of these findings to show that vegetation sciences will have an increasing role in understanding climate and its vulnerability to changes in land cover.