Search Results

You are looking at 1 - 9 of 9 items for :

  • Progress in Advancing Drought Monitoring and Prediction x
  • All content x
Clear All
Anthony M. DeAngelis, Hailan Wang, Randal D. Koster, Siegfried D. Schubert, Yehui Chang, and Jelena Marshak

,h ). Fig . 2. Observed temporal evolution of the 2012 Great Plains flash drought. Hovmöller diagrams depict anomalies as a function of longitude and time from 1 May through 31 Aug for (a) P (mm day −1 ), (b) T2m (K), (c) vapor pressure deficit at 2 m (VPD2m; hPa) (d) RZSM ( Z score), (e) surface latent heat flux (LH; W m −2 ), (f) surface sensible heat flux (SH; W m −2 ), (g) meridional wind at 200 hPa (V200; m s −1 ), and (h) geopotential height at 200 hPa (H200; dam). All anomalies are averaged

Restricted access
Keyhan Gavahi, Peyman Abbaszadeh, Hamid Moradkhani, Xiwu Zhan, and Christopher Hain

atmospheric data such as precipitation and relative humidity, or land surface data acquisition such as SM and ET. The latter can be indirectly assimilated into the land surface models to achieve more accurate and reliable predictions of hydrologic fluxes as well as for monitoring purposes ( Kumar et al. 2014 ; Pan and Wood 2006 ; Pipunic et al. 2008 ; Reichle et al. 2014 ; Sawada et al. 2015 ; Xu et al. 2020 ). SM prediction using land surface models driven by meteorological forcing carries

Open access
David M. Mocko, Sujay V. Kumar, Christa D. Peters-Lidard, and Shugong Wang

Abstract

This study presents an evaluation of the impact of vegetation conditions on a land-surface model (LSM) simulation of agricultural drought. The Noah-MP LSM is used to simulate water and energy fluxes and states, which are transformed into drought categories using percentiles over the continental U.S. from 1979 to 2017. Leaf Area Index (LAI) observations are assimilated into the dynamic vegetation scheme of Noah-MP. A weekly operational drought monitor (the U.S. Drought Monitor) is used for the evaluation. The results show that LAI assimilation into Noah-MP’s dynamic vegetation scheme improves the model's ability to represent drought, particularly over cropland areas. LAI assimilation improves the simulation of the drought category, detection of drought conditions, and reduces the instances of drought false alarms. The assimilation of LAI in these locations not only corrects model errors in the simulation of vegetation, but also can help to represent unmodeled physical processes such as irrigation towards improved simulation of agricultural drought.

Restricted access
Yaling Liu, Dongdong Chen, Soukayna Mouatadid, Xiaoliang Lu, Min Chen, Yu Cheng, Zhenghui Xie, Binghao Jia, Huan Wu, and Pierre Gentine

1. Introduction Soil moisture (SM) is an essential component of the Earth system. It affects the variability of the coupled energy (latent and sensible heat fluxes) and water fluxes (runoff and evapotranspiration) by modifying the partitioning of water and energy across the land–atmosphere interface ( Seneviratne et al. 2010 ). The effects of SM on evapotranspiration also impact temperature variability and may intrigue persistent heatwaves ( Fischer et al. 2007 ; Hirschi et al. 2011

Restricted access
Richard Seager, Jennifer Nakamura, and Mingfang Ting

. The clear exception was fall 2010 when La Niña conditions drove drying over the southern Plains and induced drought onset, a case that has been studied before (e.g., Seager et al. 2014 ). According to SNT , other onsets and terminations of drought were most likely driven by internal atmosphere variability. Their argument was essentially that while droughts, as phenomena that integrate surface moisture fluxes over time, can be driven by ocean variations and hence be potentially predictable on a

Restricted access
Kingtse C. Mo and Dennis P Lettenmaier

: A simple hydrologically based model of land surface water and energy fluxes for general circulation models . J. Geophys. Res. , 99 , 14 415 – 14 428 , https://doi.org/10.1029/94JD00483 . 10.1029/94JD00483 Liu , Y. , Y. Zhu , L. Ren , J. Otkin , E. D. Hunt , X. Yang , F. Yuan , and S. Jiang , 2020 : Two different methods for flash drought identification: Comparison of their strengths and limitations . J. Hydrometeor. , 21 , 691 – 704 , https://doi.org/10.1175/JHM

Restricted access
Chul-Su Shin, Paul A. Dirmeyer, Bohua Huang, Subhadeep Halder, and Arun Kumar

. 2016 ; Dirmeyer and Halder 2016 , 2017 ; Dirmeyer et al. 2018b ; Halder et al. 2018 ). Model fidelity in representing coupled land–atmosphere processes is also necessary, including proper simulation of variability, covariability, sensitivity, and critical transitions in the chain of processes linking land surface states to surface fluxes, near-surface atmospheric states, boundary layer characteristics, cloud formation, and precipitation ( Dirmeyer and Halder 2017 ; Santanello et al. 2018

Restricted access
Shanshui Yuan, Steven M. Quiring, and Chen Zhao

Food and Agricultural Organization ( Allen et al. 1998 ): (4) PET = 0.408 Δ ⁡ ( R n − G ) + γ   900 T + 273   U 2 ⁡ ( e a − e d ) Δ + γ ⁡ ( 1 + 0.34 U 2 ) , where is R n is net radiation at the crop surface, G is soil heat flux density, T is mean air temperature at 2-m height, U 2 is wind speed at 2-m height, e s is saturation vapor pressure, e a is actual vapor pressure, Δ is slope of vapor pressure curve, and γ is psychrometric constant. f. Meteorological data Gridded temperature

Restricted access
Yizhou Zhuang, Amir Erfanian, and Rong Fu

−1 in winter to near 3 mm day −1 in late spring and early summer ( Figs. S1a,d in the online supplemental material). Our moisture budget analysis over the Great Plains region ( Fig. S2 ) shows that, among all the moisture tendency terms, the zonal advection tendency (ADV x ) is the dominant term of moisture flux convergence (MFC) above ~800 hPa over the region year round, while the meridional advection term (ADV y ) is dominant below ~800 hPa during late spring to early fall. The horizontal

Restricted access