Droughts can have devastating societal impacts. Yet, we do not fully understand the mechanisms that control their development, possibly affecting our ability to predict them. Here we run a moisture-tracking analytical model using reanalysis data between 1980 and 2016 to explore the role of reduced moisture transport in drought propagation. We find that agricultural droughts in multiple subregions across North America may be amplified by decreased moisture transport from upwind land areas, which we link to reduced evapotranspiration and dry soil moisture upwind. We also find that decreases in precipitation recycling are correlated with decreases in moisture arriving from upwind areas. We estimate that decreases in moisture contributions from land areas accounted for 62% of the precipitation deficit during the 2012 Midwest drought. Our results suggest that the land surface may contain useful information for drought prediction and highlight the importance of sustainable land use and of regional cooperation for drought risk management.
- Agricultural droughts in upwind regions amplify agricultural droughts downwind via decreased moisture exports
- Decreases in recycled precipitation within a region are positively correlated with decreases in imported precipitation into the region
- Reduced moisture contributions from land areas accounted for 62% of the precipitation deficit in the Midwest during the 2012 drought
Plain Language Summary
Droughts reduce the availability of water, which affects communities and ecosystems worldwide. Recent studies have shown that droughts may travel up to thousands of kilometers across continents, but it is still unclear what are the reasons behind these observed drought displacements. While there may be several reasons, we study one particular way in which droughts may be able to travel across continents. Our idea is that a drought in one area may decrease evaporation locally, which will reduce water vapor in the air. As the wind blows, it will transport drier air, which may lead to less precipitation downwind. We find links between droughts that take place in different regions across North America, suggesting that droughts may travel in this way, for example, from the U.S. Southwest to the U.S. Midwest. We also show that the lower evaporation that took place over the western United States, likely due to droughts in the region in 2012, increased the severity of the drought in the U.S. Midwest that year. Our study highlights the importance of sustainable land use management and the need for coordination between communities in upwind and downwind regions to reduce drought risks. It may also help improve future drought predictions.
Droughts may cause severe damages to communities and ecosystems. However, we do not fully understand their underlying mechanisms, which limits our ability to predict them and understand how climate change may affect them (Berg & Sheffield, 2018; Roy et al., 2019; Wood et al., 2015). Two mechanisms that have been linked to drought development are precipitation recycling and moisture transport (Rodriguez-Iturbe et al., 1991; Eltahir & Bras, 1996; Dirmeyer & Brubaker, 1999; Giannini et al., 2003; Dominguez et al., 2009; D'Odorico et al., 2013; van der Ent et al., 2010; Gimeno et al., 2012; Miralles et al., 2019; Roundy et al., 2013, 2014; Roundy & Wood, 2015; Roy et al., 2019; Santanello et al., 2017; Sud et al., 2003; Wu & Kinter, 2009). Precipitation recycling is the contribution of evapotranspiration to precipitation regionally (Eltahir & Bras, 1996). High rates of precipitation recycling imply a positive feedback, where high evapotranspiration increases atmospheric water vapor, generally leading to more precipitation, increasing soil moisture, and evapotranspiration. Moisture transport refers to moisture that originates as evapotranspiration and is advected downwind, where it may eventually fall as precipitation (Dominguez et al., 2009; Roy et al., 2019).
Studying moisture transport's contributions to flooding is an active research area, especially regarding atmospheric rivers (Dirmeyer & Brubaker, 1999; Dirmeyer & Kinter, 2010; Gimeno et al., 2012; Wei et al., 2016). However, the role of moisture transport in drought development is poorly understood (Miralles et al., 2019). Recently, droughts have been shown to travel long distances and reduced moisture transport has been proposed as a mechanism (Dominguez et al., 2009; Herrera-Estrada et al., 2017; Kam, Sheffield, & Wood, 2014; Keys et al., 2018; Roy et al., 2019). The hypothesis is that droughts reduce moisture exports downwind, possibly amplifying drought conditions downwind.
Several modeling approaches, including analytical models, have been developed to study moisture transport and precipitation recycling (Gimeno et al., 2012). We use the analytical model developed by Dominguez et al. (2006) and extended by Martinez and Dominguez (2014) to perform the first climatological analysis over North America that investigates how moisture transport may be linked to drought propagation. We also use this framework to diagnose the development of the U.S. Midwest drought in 2012.
2.1 The Dynamic Recycling Model
The Dynamic Recycling Model (DRM; Dominguez et al., 2006; Martinez & Dominguez, 2014) estimates how much precipitable water and precipitation that falls daily throughout the domain originates from evapotranspiration over defined subregions. We then calculate the volumes of precipitation that fall each month in each subregion that originate from evapotranspiration within and outside that subregion. The subregions have different areas, so we use these volumetric rates (km3/month) throughout our study instead of recycling ratios. Supporting information Text S1 includes further information on the DRM.
The DRM is designed to run using daily precipitation, evapotranspiration, and vertically integrated water vapor, and 6-hourly eastward and northward vertically integrated water vapor fluxes (Dominguez et al., 2006; Martinez & Dominguez, 2014). We run the DRM between 1980 and 2016 using ERA-Interim data (Dee et al., 2011) at 0.75° resolution. ERA-Interim's hydrological cycle has been validated (Balsamo et al., 2015) and shown to be more accurate than other reanalysis products (Lorenz & Kunstmann, 2012). Numerous studies have driven moisture transport models using ERA-Interim (e.g., Agudelo et al., 2018; Keys et al., 2014; Martinez & Dominguez, 2014; Pathak et al., 2016; van der Ent et al., 2010). We also use ERA-Interim's monthly volumetric soil water (0–1 m) to characterize agricultural drought.
We select a large domain to capture the possible moisture sources of the region of interest. The full domain lies within 170–140°W and 0–70°N (Figure 1a). The core land domain, between 130–60°W and 16–51.5°N, includes Mexico, the contiguous United States, and southern Canada. The core domain is divided into 15 subregions, while land areas at lower and higher latitudes are divided into 5. The Pacific Ocean is divided into four subregions and the Atlantic Ocean into three. Table S1 displays the subregions' names and areas.
2.4 Spatial Propagation
We define agricultural droughts as the instances when soil moisture falls below the 20th percentile (calculated following Andreadis et al., 2005). We call “precipitation exports” the precipitation that falls outside of a subregion but originates from evapotranspiration within it (Dirmeyer, Brubaker, et al., 2009; Zemp et al., 2014). Conversely, we call “precipitation imports” the precipitation that falls within a subregion but originates from evapotranspiration outside of it.
We identify pairs of upwind-downwind land subregions between which agricultural drought may have propagated via decreased moisture transport between 1980 and 2016. For each land subregion, we calculate monthly time series of the following: soil moisture, evapotranspiration, total precipitation exports from that subregion, total precipitation imports into that subregion, and precipitation exports-imports between that subregion and the other land subregions. We identify the instances when soil moisture, evapotranspiration, total exports, and total imports fall below their respective 20th percentiles. For each subregion in the core domain, we also calculate the monthly anomalies of total precipitation imports and the monthly anomalies of precipitation imports from each other land subregion. We calculate monthly anomalies by subtracting the respective monthly mean from each individual monthly value.
- Soil moisture values in the two subregions are below their respective 20th percentiles;
- evapotranspiration over A and total exports from A are below their respective 20th percentiles;
- total precipitation imports into B are below the 20th percentile;
- there is a negative anomaly of total precipitation imports into B that is larger in magnitude than the negative anomaly of precipitation exports from A to B; and
- the negative anomaly of precipitation exports from A to B is at least 30% of the negative anomaly of total precipitation imports into B.
Condition #1 confirms that there is an agricultural drought in both subregions, while condition #2 checks whether the decreased precipitation exports from A to B may be linked to a decrease in evapotranspiration associated with the agricultural drought in A. Condition #3 checks that there is a meteorological drought over B, and condition #4 checks that the reduced exports from A to B are a fraction of the total deficit. Condition #4 also checks that the precipitation deficit from A is not offset by precipitation from other subregions, which would make the total precipitation deficit over B smaller than the precipitation deficit from A to B. Finally, condition #5 ensures that the fraction of the deficit attributed to decreased moisture exports from A to B is substantial. If all conditions are met during at least 1 month, we suggest that a drought may have propagated from A to B, draw a link between the two regions, and record the season of occurrence.
We repeat this analysis for all land subregions as upwind sources and land subregions in the core domain as downwind sinks. To test our results' sensitivity, we repeat this analysis using combinations of 10th and 20th percentile thresholds to define agricultural drought and 10%, 30%, and 50% thresholds for condition #5.
2.5 Regional Intensification
2.6 U.S. Midwest Drought (2012)
We study the changes in moisture transport and precipitation recycling during the 2012 meteorological and agricultural droughts in the Midwest within a climatological context. Our hypothesis is that reduced precipitation recycling and moisture transport from upwind land sources may have amplified the Midwestern drought. Using the DRM, we identify the precipitation deficits over the Midwest associated to precipitation recycling and to reduced moisture transport from upwind subregions. We repeat this analysis for land areas upwind from the Midwest that were under agricultural drought to track the development of the meteorological and agricultural droughts over the broader region.
We define the Midwest by subregions 11 and 16 (Figure 1a) and define the start of the agricultural drought as the month when soil moisture in both Midwestern subregions falls below the 20th percentile. We define the agricultural drought's peak as the month with the lowest soil moisture percentile in both subregions and the drought's end as the month when soil moisture increases above the 20th percentile. We analyze the evolution of the meteorological drought within these fixed time periods of agricultural drought onset and recovery.
We calculate the total precipitation deficit over the Midwest subregions by adding the precipitation anomalies from the start to the peak of the agricultural drought. We then find the subregions that accounted for at least 10% of the total precipitation deficit over each Midwestern subregion. If the identified upwind land subregions also experienced agricultural drought during this period, we repeat the analysis by calculating the total precipitation deficits over the subregions and identifying what subregions accounted for at least 10% of their respective total deficits. We use a 10% threshold (instead of 30% as in section 2.4) to identify more upwind subregions that contributed to the deficits. We explore possible drivers of the reduced precipitation recycling and moisture transport by examining the time series of soil moisture percentiles, total evapotranspiration, and total precipitation exports from the upwind land subregions that accounted for at least 10% of the total precipitation deficit over the Midwest.
We analyze the drought's recovery by calculating the total precipitation that fell over the Midwest between the peak and the end of the agricultural drought and finding the subregions that accounted for at least 10% of the total precipitation during this period. If other land subregions are identified, we repeat the analysis to identify the subregions that contributed to their recovery. We use absolute precipitation amounts instead of positive precipitation anomalies because any precipitation contributes to the recovery of an agricultural drought.
Figure 1b and Tables S2 and S3 show the mean yearly precipitation exports-imports (1980–2016) between four aggregate land regions and imports from the oceans. Greater Mexico and the western United States receive ~70% of precipitation from the oceans and ~23% from internal recycling. Upwind land sources provide the remainder (7% and 8%, respectively). In central and eastern United States, 45–51% of the precipitation comes from the oceans, 35–39% from upwind land regions, and 14–15% is internally recycled. Table S2 displays these percentages for each subregion, and Figure S1 shows the monthly means of precipitation exports, imports, and recycling for each subregion. Figure 1c and Table S4 show the mean precipitation imports into the Midwest, highlighting that the top contributors are the Pacific Ocean (40% of yearly precipitation), the western United States (30%), and internal recycling (13%).
3.1 Spatial Propagation
Figure 2 summarizes the results from the methodology of section 2.4. These maps show the upwind and downwind subregions between which agricultural droughts may have propagated between 1980 and 2016. For example, droughts may have propagated from the U.S. Southwest (R8) and the Pacific Coast (R7 and R14) to the Central Rockies (R10). Subsequently, droughts in the Central Rockies (R10) may have propagated to the Upper Rockies (R15), the Midwest (R11 and R16), the U.S. Southeast (R6), the Mid-Atlantic (R12), and Southeast Canada (R17). Also, linked subregions tend to be adjacent. For example, the Northwest of Mexico (R4) is linked to the U.S. Southwest (R8), which is linked to the Central Rockies (R10). Figure S2 shows the sensitivity of the identified links to the chosen thresholds. While some links are not highlighted in Figure 2 (e.g., R9 upwind from R11), they appear in this sensitivity analysis.
Figure S3 shows how frequently these links were drawn during each season. We found 19 links of agricultural drought propagation between June and August, 12 between March and May, 6 between September and November, and 3 between December and February. Thus, drought propagation via decreased moisture transport appears to be primarily a warm-season phenomenon. The number of links between each pair of subregions indicates the link's strength (e.g., recurring links between the Upper Rockies [R15] and the Upper Midwest [R16]).
3.2 Regional Intensification
Precipitation recycling has a multiplier effect (Savenije, 1995; van der Ent et al., 2010), amplifying an anomaly of imported precipitation. The DRM partitions the precipitation that falls within a subregion as originating from evapotranspiration within the subregion (recycled) or outside the subregion (imported). We quantify the empirical relationship between reductions in recycled and imported precipitation.
Figure 3 shows the percentage decreases in precipitation recycling correlated to a 1% decrease in imported precipitation. Values between 0.9 and 1 represent an almost equal relative decrease in imported and recycled precipitation. Values above 1 represent larger decreases in recycling relative to decreases in imported precipitation, suggesting an amplification effect. Figures 3 and S4 show that there are significant decreases in recycling correlated with decreases in imported precipitation in the Pacific Southwest (R7), U.S. Southwest (R8), Central Rockies (R10), and Upper Rockies (R15). Decreases in recycling may be driven by reduced atmospheric water vapor due to low evaporation or by inhibition of precipitation triggers due to dry soils (Findell & Eltahir, 2003a, 2003b; Roundy et al., 2013). Our framework cannot isolate the specific mechanisms that reduce recycling, so their identification is beyond this study's scope.
3.3 Midwest Drought (2012)
We calculate the moisture transport and recycling changes during the 2012 Midwest drought (Hoerling et al., 2014; Kam et al., 2014) using the framework introduced by Herrera Estrada (2017) and implemented by Roy et al. (2019). This drought caused substantial agricultural damages and was not adequately predicted (Hoerling et al., 2014; Kam, Sheffield, Yuan, et al., 2014; Roy et al., 2019).
Figure 4a shows time series of soil moisture percentiles for the two Midwestern subregions and three other land subregions that played key roles during the drought onset (Figure 4b). We find that the agricultural drought in the two Midwestern subregions started in August 2011, peaked in August 2012, and recovered by March 2013. Figure 4b shows the accumulated precipitation deficits over the Midwest and the land subregions that contributed directly and indirectly to the Midwest's deficit during the onset period. The Lower Midwest (R11) experienced the largest deficit (−233.1 km3) over the 13-month period leading to the agricultural drought's peak. Deficits from the Pacific Ocean (R23–R26, −70.0 km3), Central Rockies (R10, −33.9 km3), and U.S. Southwest (R8, −25.5 km3) accounted for most of the Lower Midwest's deficit. Decreased recycling added −30.7 km3 and smaller contributions from 22 regions contributed the remaining −73.0 km3 of the total deficit.
Figure 4a shows that these upwind land subregions were also under agricultural drought. The Pacific Ocean, the Pacific Southwest (R7), and decrease recycling accounted for most of the precipitation deficit in the Central Rockies (R10). Similarly, reduced precipitation from the Pacific Ocean and from recycling contributed the most to the precipitation deficit in the U.S. Southwest (R8). Examining time series of the anomalies in evapotranspiration, total exports, total imports, and recycling over each of these land subregions (Figure S5) suggests that the decreases in precipitation exports from the land subregions upwind from the Midwest may be linked to lower-than-average evapotranspiration, possibly due to the agricultural drought (Figure 4a).
Decreased precipitation from the Pacific Ocean contributed directly and indirectly to the development of the meteorological and agricultural droughts over the Midwest and the western United States. However, decreased moisture transport from the land surface and precipitation recycling may have played an important role in amplifying drought conditions. Figure S6a shows the precipitation deficits from each subregion to the two Midwestern subregions combined. Decreased precipitation originating from upwind land subregions and from recycling accounted for 47.5% and 14.4%, respectively, of the total precipitation deficit. Overall, reduced precipitation from land sources amounted to 61.9% of the total deficit compared to 37.9% from the oceans.
The drought's recovery in the Midwest was driven mostly by precipitation arriving directly from the Pacific Ocean, which may have restarted recycling (Figures S5 and S6). Although the agricultural drought in the Midwest recovered by March 2013, droughts in the western United States persisted (Figure 4a).
4 Discussion and Conclusions
We identify subregions across North America between which agricultural droughts may have propagated through decreased moisture transport. We find that droughts in the western United States may amplify droughts in downwind subregions including the Midwest, consistent with Dominguez et al. (2009). Further, linked subregions tend to be adjacent to each other, providing a possible mechanism by which droughts may travel across continents (Herrera-Estrada et al., 2017). Displacement of high-pressure systems and shifts in general circulation patterns may be other possible mechanisms of drought propagation (Hoerling et al., 2014; Wei et al., 2012; Wei et al., 2016). Further work is needed to understand the effects of large-scale circulation on moisture transport and drought propagation (Kam, Sheffield, & Wood, 2014; Wei et al., 2012).
We show that in the western United States, decreases in precipitation recycling are strongly correlated with reductions in imported precipitation, supporting the hypothesis that regional positive feedbacks may amplify decreases in moisture transport into a region. We also find that precipitation recycling may increase as moisture begins to arrive from the surroundings. During the recovery of the 2012 Midwest drought, most of the precipitation arrived from the Pacific Ocean, possibly helping restart recycling.
The DRM assumes a well-mixed atmosphere because most of the recycled moisture is found within the planetary boundary layer, which efficiently mixes the air via turbulent processes (Eltahir & Bras, 1996). However, the well-mixed assumption is generally not met in regions of strong vertical wind shear and where the contribution of water vapor from a certain vertical level to precipitation is very different from that level's mixing ratio (Bosilovich, 2002; Dominguez et al., 2016; Goessling & Reick, 2013; van der Ent et al., 2013). In our study, this assumption may overestimate the precipitation that the model tracks across mountainous regions, particularly in the western United States, leading to uncertainties in the relative contributions from the oceans to inland regions. Qualitative comparisons with Dirmeyer and Brubaker (1999), Dirmeyer, Brubaker, et al. (2009), and Duerinck et al. (2016) show that our study potentially overestimates the precipitation contributions from the Pacific Ocean to the Midwest (not shown). Thus, our estimates of the land-surface's contributions to moisture exports to the Midwest are possibly conservative. A more accurate representation of moisture fluxes across mountains would likely increase the relative importance of precipitation originating from land compared to that from the Pacific Ocean. The DRM is a computationally efficient tool comparable in many cases to sophisticated three-dimensional methods (e.g., Hoyos et al., 2017), but generally provides first-order estimates of moisture sources and sinks.
We use simultaneous occurrences of hydroclimatological conditions to link upwind and downwind regions, and linear regressions to quantify the empirical relationships between changes in imported and recycled precipitation. While circumstantial evidence and correlations are certainly not equivalent to causation, our methodology is built on hypotheses derived from our understanding of moisture transport and precipitation recycling allowing us to draw insights into their role regarding drought propagation. To further isolate the land-surface's effect on drought propagation and intensification, future studies can involve climate modeling experiments that compare the spatiotemporal dynamics of agricultural droughts when soil moisture is fixed to climatology and when it is allowed to evolve dynamically.
Our results suggest that multiple droughts over a continent should not necessarily be conceived as resulting from random atmospheric variability (e.g., Seager et al., 2013). Instead, there may be important teleconnections across the land surface that can propagate and amplify droughts. Our analysis focuses on North America but we expect that moisture transport may play a similarly important role in the spatial propagation of droughts in other regions (e.g., Zemp et al., 2014). This novel conceptualization of drought development may help diagnose past droughts and improve seasonal forecasts (Dirmeyer, Schlosser, et al., 2009; Findell & Eltahir, 1997; Guo et al., 2012; Roundy et al., 2014; Roundy & Wood, 2015; Roy et al., 2019; Wood et al., 2015). Our results raise the importance of sustainable land use practices in upwind regions on which downwind communities rely for precipitation (DeAngelis et al., 2010; Findell et al., 2009; Findell et al., 2017; Keys et al., 2016, 2018; Mahmood et al., 2014; Wang-Erlandsson et al., 2017; Yang et al., 2017). These results also raise questions regarding governance of transboundary precipitationsheds (Dirmeyer, Brubaker, et al., 2009; Keys et al., 2012, 2014, 2017, 2018) and cooperation between upwind and downwind communities for drought risk management.
We thank the Terrestrial Hydrology Research Group (Princeton University), the Climate and Earth System Dynamics Group (Stanford University), Ruud van der Ent, Jiangfeng Wei, Krista Dunne, Fanrong Zeng, and Gabrielle Girard for their feedback. Funding was provided by the NASA Earth and Space Science Fellowship (NNX14AL08H), NOAA award NA15OAR4310091, and Stanford University's Program on Water in the West. F. D. was funded by NSF award 1454089 and J. A. M. by Comite Desarrollo Investigación (CODI) Award 2017-16264. ERA-Interim data are available at the https://www.ecmwf.int/ website. Data used to produce the figures are included as supporting information.
|grl58908-sup-0001-2019GL082475-Text_SI-S01.docxWord 2007 document , 3.1 MB||Supporting Information S1|
|grl58908-sup-0002-2019GL082475-Data_Set_SI-S01.xlsxExcel 2007 spreadsheet , 219.7 KB||Data Set S1|
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- 2018). Influence of longer dry seasons in the Southern Amazon on patterns of water vapor transport over northern South America and the Caribbean. Climate Dynamics. https://doi.org/10.1007/s00382-018-4285-1
- 2005). Twentieth-century drought in the conterminous United States. Journal of Hydrometeorology, 6(6), 985–1001. https://doi.org/10.1175/JHM450.1
- 2015). ERA-Interim/Land: A global land surface reanalysis data set. Hydrology and Earth System Sciences, 19(1), 389–407. https://doi.org/10.5194/hess-19-389-2015
- 2018). Climate change and drought: The Soil moisture perspective. Current Climate Change Reports, 4(2), 180–191. https://doi.org/10.1007/s40641-018-0095-0
- 2002). On the vertical distribution of local and remote sources of water for precipitation. Meteorology and Atmospheric Physics, 80(1–4), 31–41. https://doi.org/10.1007/s007030200012
- 2010). Evidence of enhanced precipitation due to irrigation over the Great Plains of the United States. Journal of Geophysical Research, 115, D15115. https://doi.org/10.1029/2010JD013892
- 2011). The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quarterly Journal of the Royal Meteorological Society, 137(656), 553–597. https://doi.org/10.1002/qj.828
- 1999). Contrasting evaporative moisture sources during the drought of 1988 and the flood of 1993. Journal of Geophysical Research, 104(D16), 19,383–19,397. https://doi.org/10.1029/1999JD900222
- 2009). Import and export of atmospheric water vapor between nations. Journal of Hydrology, 365(1–2), 11–22. https://doi.org/10.1016/j.jhydrol.2008.11.016
- 2010). Floods over the U.S. Midwest: A regional water cycle perspective. Journal of Hydrometeorology, 11(5), 1172–1181. https://doi.org/10.1175/2010JHM1196.1
- 2009). Precipitation, recycling, and land memory: An integrated analysis. Journal of Hydrometeorology, 10(1), 278–288. https://doi.org/10.1175/2008JHM1016.1
- 2013). Global desertification: Drivers and feedbacks. Advances in Water Resources, 51, 326–344. https://doi.org/10.1016/j.advwatres.2012.01.013
- 2006). Impact of atmospheric moisture storage on precipitation recycling. Journal of Climate, 19(8), 1513–1530. https://doi.org/10.1175/JCLI3691.1
- 2016). WRF with water vapor tracers: A study of moisture sources for the North American Monsoon. Journal of Hydrometeorology, 17(7), 1915–1927. https://doi.org/10.1175/JHM-D-15-0221.1
- 2009). Spatial extent of the North American Monsoon: Increased cross-regional linkages via atmospheric pathways. Geophysical Research Letters, 36, L07401. https://doi.org/10.1029/2008GL037012
- 2016). Observed soil moisture–precipitation feedback in Illinois: A systematic analysis over different scales. Journal of Hydrometeorology, 17(6), 1645–1660. https://doi.org/10.1175/JHM-D-15-0032.1
- 1996). Precipitation recycling. Reviews of Geophysics, 34(3), 367–378. https://doi.org/10.1029/96RG01927
- 2017). The impact of anthropogenic land use and land cover change on regional climate extremes. Nature Communications, 8(1), 989. https://doi.org/10.1038/s41467-017-01038-w
- 1997). An analysis of the soil moisture-rainfall feedback, based on direct observations from Illinois. Water Resources Research, 33(4), 725–735. https://doi.org/10.1029/96WR03756
- 2003a). Atmospheric controls on soil moisture–boundary layer interactions. Part I: Framework development. Journal of Hydrometeorology, 4(3), 552–569. https://doi.org/10.1175/1525-7541(2003)004<0552:ACOSML>2.0.CO;2
- 2003b). Atmospheric controls on soil moisture–boundary layer interactions. Part II: Feedbacks within the continental United States. Journal of Hydrometeorology, 4(3), 570–583. https://doi.org/10.1175/1525-7541(2003)004<0570:ACOSML>2.0.CO;2
- 2009). Regional and global impacts of land cover change and sea surface temperature anomalies. Journal of Climate, 22(12), 3248–3269. https://doi.org/10.1175/2008JCLI2580.1
- 2003). Oceanic forcing of Sahel rainfall on Interannual to interdecadal time scales. Science, 302(5647), 1027–1030. https://doi.org/10.1126/science.1089357
- 2012). Oceanic and terrestrial sources of continental precipitation. Reviews of Geophysics, 50, RG4003. https://doi.org/10.1029/2012RG000389
- 2013). On the “well-mixed” assumption and numerical 2-D tracing of atmospheric moisture. Atmospheric Chemistry and Physics, 13(11), 5567–5585. https://doi.org/10.5194/acp-13-5567-2013
- 2012). Rebound in atmospheric predictability and the role of the land surface. Journal of Climate, 25(13), 4744–4749. https://doi.org/10.1175/JCLI-D-11-00651.1
- 2017). Advances in understanding the causes and impacts of droughts in North America under current and future climates (Order No. 10637641). Available from ProQuest Dissertations & Theses Global. (1972083865). Retrieved from. https://search.proquest.com/docview/1972083865?accountid=14026
- 2017). Spatiotemporal dynamics of global drought. Geophysical Research Letters, 44, 1–25. https://doi.org/10.1002/2016GL071768
- 2014). Causes and Predictability of the 2012 Great Plains Drought. Bulletin of the American Meteorological Society, 95(2), 269–282. https://doi.org/10.1175/BAMS-D-13-00055.1
- 2017). Moisture origin and transport processes in Colombia, northern South America. Climate Dynamics, 50(3–4), 971–990. https://doi.org/10.1007/s00382-017-3653-6
- 2014). A multiscale analysis of drought and pluvial mechanisms for the Southeastern United States. Journal of Geophysical Research: Atmospheres, 119, 7348–7367. https://doi.org/10.1002/2014JD021453
- 2014). Did a skillful prediction of sea surface temperatures help or hinder forecasting of the 2012 Midwestern US drought? Environmental Research Letters, 9, 34005. https://doi.org/10.1088/1748-9326/9/3/034005
- 2014). Variability of moisture recycling using a precipitationshed framework. Hydrology and Earth System Sciences, 18(10), 3937–3950. https://doi.org/10.5194/hess-18-3937-2014
- 2012). Analyzing precipitationsheds to understand the vulnerability of rainfall dependent regions. Biogeosciences, 9(2), 733–746. https://doi.org/10.5194/bg-9-733-2012
- 2016). Revealing invisible water: Moisture recycling as an ecosystem service. PLoS ONE, 11(3), e0151993. https://doi.org/10.1371/journal.pone.0151993
- 2018). Megacity precipitationsheds reveal tele-connected water security challenges. PLoS ONE, 13(3), e0194311. https://doi.org/10.1371/journal.pone.0194311
- 2017). Approaching moisture recycling governance. Global Environmental Change, 45, 15–23. https://doi.org/10.1016/j.gloenvcha.2017.04.007
- 2012). The hydrological cycle in three state-of-the-art reanalyses: Intercomparison and performance analysis. Journal of Hydrometeorology, 13(5), 1397–1420. https://doi.org/10.1175/JHM-D-11-088.1
- 2014). Land cover changes and their biogeophysical effects on climate. International Journal of Climatology, 34(4), 929–953. https://doi.org/10.1002/joc.3736
- 2014). Sources of atmospheric moisture for the La Plata River basin. Journal of Climate, 27(17), 6737–6753. https://doi.org/10.1175/JCLI-D-14-00022.1
- 2019). Land-atmospheric feedbacks during droughts and heatwaves: State of the science and current challenges: Land feedbacks during droughts and heatwaves. Annals of the New York Academy of Sciences, 1436(1), 19–35. https://doi.org/10.1111/nyas.13912
- 2016). Role of oceanic and land moisture sources and transport in the seasonal and inter-annual variability of summer monsoon in India. Journal of Climate. https://doi.org/10.1175/JCLI-D-16-0156.1
- 1991). Nonlinear dynamics of soil moisture at climate scales: 1. Stochastic analysis. Water Resources Research, 27(8), 1899–1906. https://doi.org/10.1029/91WR01035
- 2013). Temporal variability of land–atmosphere coupling and its implications for drought over the southeast United States. Journal of Hydrometeorology, 14(2), 622–635. https://doi.org/10.1175/JHM-D-12-090.1
- 2014). Impact of land-atmospheric coupling in CFSv2 on drought prediction. Climate Dynamics, 43(1–2), 421–434. https://doi.org/10.1007/s00382-013-1982-7
- 2015). The attribution of land–atmosphere interactions on the seasonal predictability of drought. Journal of Hydrometeorology, 16(2), 793–810. https://doi.org/10.1175/JHM-D-14-0121.1
- 2019). Role of moisture transport and recycling in characterizing droughts: Perspectives from two recent US droughts and the CFSv2 system. Journal of Hydrometeorology, 20, 139–154. https://doi.org/10.1175/JHM-D-18-0159.1
- 2017). Land-atmosphere interactions: The LoCo Perspective. Bulletin of the American Meteorological Society, 99(6), 1253–1272. https://doi.org/10.1175/BAMS-D-17-0001.1
- 1995). New definitions for moisture recycling and the relationship with land-use changes in the Sahel. Journal of Hydrology, 167(1), 57–78. https://doi.org/10.1016/0022-1694(94)02632-L
- 2013). Dynamical causes of the 2010/11 Texas–Northern Mexico drought. Journal of Hydrometeorology, 15(1), 39–68. https://doi.org/10.1175/JHM-D-13-024.1
- 2003). Simulating the Midwestern US drought of 1988 with a GCM. Journal of Climate, 16(23), 3946–3965. https://doi.org/10.1175/1520-0442(2003)016<3946:STMUDO>2.0.CO;2
- 2010). Origin and fate of atmospheric moisture over continents. Water Resources Research, 46, W09525. https://doi.org/10.1029/2010WR009127
- 2013). Should we use a simple or complex model for moisture recycling and atmospheric moisture tracking? Hydrology and Earth System Sciences, 17(12), 4869–4884. https://doi.org/10.5194/hess-17-4869-2013
- 2017). Remote land use impacts on river flows through atmospheric teleconnections. Hydrology and Earth System Sciences Discussions, 1–17. https://doi.org/10.5194/hess-2017-494
- 2012). Water vapor sources for Yangtze River Valley rainfall: Climatology, variability, and implications for rainfall forecasting. Journal of Geophysical Research, 117, D05126. https://doi.org/10.1029/2011JD016902
- 2016). Role of ocean evaporation in California droughts and floods. Geophysical Research Letters, 43, 6554–6562. https://doi.org/10.1002/2016GL069386
- 2015). Prospects for advancing drought understanding, monitoring, and prediction. Journal of Hydrometeorology, 16(4), 1636–1657. https://doi.org/10.1175/JHM-D-14-0164.1
- 2009). Analysis of the relationship of U.S. droughts with SST and soil moisture: Distinguishing the time scale of droughts. Journal of Climate, 22(17), 4520–4538. https://doi.org/10.1175/2009JCLI2841.1
- 2017). Impact of irrigation over the California Central Valley on regional climate. Journal of Hydrometeorology, 18(5), 1341–1357. https://doi.org/10.1175/JHM-D-16-0158.1
- 2014). On the importance of cascading moisture recycling in South America. Atmospheric Chemistry and Physics, 14(23), 13,337–13,359. https://doi.org/10.5194/acp-14-13337-2014
References From the Supporting Information
- 1993). Estimation of continental precipitation recycling. Journal of Climate, 6(6), 1077–1089. https://doi.org/10.1175/1520-0442(1993)006<1077:EOCPR>2.0.CO;2
- 2006). Bulk recycling models with incomplete vertical mixing. Part II: Precipitation recycling in the Amazon basin. Journal of Climate, 19(8), 1473–1489. https://doi.org/10.1175/JCLI3688.1
- 2001). The estimation of regional precipitation recycling. Part I: Review of recycling models. Journal of Climate, 14(12), 2497–2508. https://doi.org/10.1175/1520-0442(2001)014<2497:TEORPR>2.0.CO;2
- 2014). Evaluation of oceanic and terrestrial sources of moisture for the North American Monsoon using numerical models and precipitation stable isotopes. Journal of Hydrometeorology, 16(1), 19–35. https://doi.org/10.1175/JHM-D-14-0073.1