Hydroclimatology: The Missing Component of PUB

1. Hydroclimatology: The Missing Component of PUB Praveen Kumar Francina Dominguez, Geremew Amenu Institute for Sustainability of Intensively Managed Landscapes Department of Civil & Environmental Engineering University of Illinois Urbana, Illinois 61801

2. “Hydrologists spend too much time thinking about water” Ciaran Harman

3. Global Water Vapor

4. Amenu, G.G. and P. Kumar, BAMS, 86(2), pp. 245-256, 2005.

5. Underlying Question • How do the atmospheric and terrestrialmoisture, and vegetation interact to produce the observed variability in the water cycle? • How is this variability altered by anthropogenic influences? • Energy Cycle • Water Cycle Pm E

6. Atmospheric Anomalies Enhancement or Dissipation of Anomalies through Feedback Ocean-atmosphere feedback Feedback between atmosphere and deep layer processes? Land Near surface processes Ocean Ocean Feedback between near- and deep-surface processes Deep layer processes

7. Hypothesis • Regional atmospheric moisture transport is governed by both the large scale forcing as well as local recycling, and their relative contributions have important implications in the inter-annual variability of the hydrologic cycle. • The deep layer terrestrial moisture and energy storage modulate the dynamics of the near-surface layer thereby influencing the land-atmosphere interaction.

8. Precipitation Recycling • Motivation: • Changes in land surface hydrology will affect regional climate variables (eg. precipitation). • Humans affect land surface, e. g. deforestation in Amazon. Araca River, Brazil. Landsat 7 WRS http://landsat.gsfc.nasa.gov/earthasart/araca.html

9. The principle for all analytic recycling models is the conservation of atmospheric mass • Analytic Models that assume negligible dw/dt: • Budyko (1974) • Drozdov and Grigor’eva (1965) • Lettau et al. (1979) • Brubaker et al. (1993) • Eltahir and Bras (1994) • Savenije (1995) • Burde and Zangvil (2001) All previous recycling models have assumed negligible change of storage of atmospheric water vapor.

10. While the storage term is smaller than the advection terms, it is nonegligible at a daily timescale Monthly Storage term is small compared to advection at a monthly timescale. At the daily level, it is approximately 50% as large as the advection terms. - Using NCEP/NCAR Reanalysis II data from 1979-2001. Daily

11. Assumption: Well mixed atmosphere. Consequently, older models are not applicable at smaller time scales. Important Land - Atmosphere Interactions occur at this timescale. Season Week Decade Month Hour Minute Day Year Recycling can be now studied at daily, weekly, and longer timescales. Dominguez, F. and P. Kumar, “Impact of Atmospheric Moisture Storage on Precipitation Recycling,” Journal of Climate, 19 (8), pages 1513–1530, 2006.

12. -.5 -.43 -.37 -.3 -.23 -.17 -.1 -.03 .03 .1 .17 .23 .3 .37 .43 .5 Correlation between daily recycling ratio and precipitation shows different sign in the east/west. Soil Moisture climatology presents a similar pattern. Correlation of Monthly Summer (JJA) 1979-2000 Recycling Ratio and Corresponding PDSI

13. Understanding the physical mechanisms that drive recycling variabilityat the Daily to Intraseasonal Timescale We choose two regions because of their contrasting land surface response to precipitation. Semi-arid North American Monsoon Region. Moisture-abundant Midwestern United States.

14. The Dynamical Recycling Model is used to calculate the recycling ratios The NARR data provides land-atmosphere variables Multichannel Singular Spectrum Analysis (M-SSA)

15. 13.1 10.2 12.1 10.4 13.2 14.3 CEC Level II Ecoregions of NA The NAMS region is composed of a variety of ecoregions, from deserts (lightest green) to tropical dry forests (darkest green). Upper Gila Mountains Sonoran Desert Western sierra Madre Piedmont Chihuahuan Desert Western Sierra Madre Western Pacific Coastal Plain Hills And Canyons

16. In the NAMS region, evapotranspiration significantly contributes to precipitation after monsoon onset. At the peak of the season, an average of 15% of precipitation comes from evapo-transpiration, although some days it can be as high as 25%.

17. Precipitation, evapotranspiration and vegetation greenness is higher in the southwest of the region Precipitation (mm/day) Recycled Precipitation (mm/day) Evapo-transpiration (mm/day) NDVI 7.2 0 0.7 0 0 4 0 1.5 Evapotranspiration is transported north and east where it falls as precipitation of recycled origin.

18. The three longest monsoons in the 1985-1995 period are characterized by two precipitation peaks. Precipitation recycling peaks during the intermediate dry period (midsummer drought - also called veranillo or canicula).

19. During long monsoons, even when precipitation decreases, ET continues to provide moisture to the overlying atmosphere. Recycling continues during dry season. No effect on NDVI Low Mid-Summer Precip No effect on Evaporation Recycling Ratio Evapo-transpiration (mm/day) NDVI Precipitation (mm/day) Region 14.3, Seasonally Dry Tropical Forest

20. The seasonally dry tropical forests of Mexico have an annual deforestation rate of 1.4% (Trejo and Dirzo, 2004). The region faces sever damage to existing vegetation health and consequently evapotranspiration regimes. Our results show that this could have important consequences for precipitation regimes.

22. Hydraulic Redistribution by Plant Roots:A Mechanism of Interaction between Moisture Reservoir of Deep-Soil, the Near-Surface Soil, and the Atmosphere

23. L1 L2 L3 10 cm   20 cm L10 L11 20 cm  20 cm each 20 cm 10 cm Global Datasets Ground Observations: • Very few locations, with poor spatial and temporal coverage • Illinois dataset is exceptionally unique dataset available Remote Sensing: • Only near-surface soil moisture is measured • No long-term data

24. Soil Moisture Power Spectra Layer 5 70-90 cm Layer1 0-10 cm Layer 3 30-50 cm Layer 7 110-130 cm Layer 9 150-170 cm Layer 11 190-200 cm Amenu, G.G., and P. Kumar, “Deep‑Layer Terrestrial Memory and Mechanisms of Its Influence on Land-Atmosphere Interaction,” Journal of Climate, 18, 5024 – 5045, 2005.

25. (4/3) ENSO T ≈ 1.5 yrs Singular Spectrum Analysis (SSA) is used to extract the dominant modes Quasi-Quadrennial (QQ) ENSO T ≈ 5 yrs Annual Cycle T = 1 yr Quasi-Biennial (QB) ENSO T ≈ 2.8 yrs The (4/3) ENSO is a result of nonlinear interaction (sub-harmonic frequency locking) between the Quasi-Quadrennial and the Annual modes.

26. ≈ 2 m ≈ 5 m Aclimatization Strategies by Vegetation

27. Plant roots are much deeper than traditionally thought in our modeling approaches. In particular, this is true for water-limited environments Based on the study by Canadell et al. (1996) & Kleidon and Heimann (1998)

28. Hydraulic Redistribution is the passive transport of soil water via plant roots from wet soil layers to dry soil layers. During day: the greatest water potential gradient in the plant exists between the roots and the leaf stomata. As a result of this gradient, water moves from the roots and exits the transpiring leaves. During night: the stomata closes, but water continues to flow into the deeper taproots. These results in turgor pressure that increases water potential within the plant body, and finally start to efflux from the roots into the drier soil.

29. Water Uptake Pattern Rambal (1984) identified four patterns of water uptake in Quercus coccifera during a dry summer season. In late spring, water loss occurred exclusively from the top 0-50 cm soil layer. In early summer, peak water uptake occured between 2 and 2.5 m depth. Late summer, the deepest soil layers were contributing much of the water. In early fall at the end of the dry period, all the layers were depleted.

30. Evidences of Hydraulic Redistribution

31. Xylem Phloem Water flow the plant system

32. Flow in the root xylem Hydraulic Redistribution Flow in the soil pores Flow into the root from the soil Root Soil Hydraulic Redistribution by plant roots can be modeled by coupling water flow within the soil media and the root media, where flow in both media is governed by water potential gradient and hydraulic conductivity of the system.

33. Boundary of study site Sierra Nevada Fresno CASE STUDY SITE: The major PFTs at the site include C3 grasses (52%), needle leaf evergreen temperate trees (46%), and broadleaf deciduous temperate trees (2%)

34. Application Example

35. Application Example

37. Are hydroclimatology and ecohydrology two sides of the same coin? • Optimality Hypothesis: evolutionary selection pressures drive ecosystems towards a state of maximum utilization of available light, water and nutrient resources for the production of biomass • Acclimatization Hypothesis:Vegetation form and function from the canopy to the ecosystem scale are a reflection of the acclimatization strategies adopted by the vegetation to maximize CO2-assimilation in the presence of the spatial and temporal variability of the controlling factors • Complexity Hypothesis: Co-evolution of the eco-hydrologic environment and vegetation patterns and functioning, in the presence of complex non-linear feedbacks results in self-organization

39. Longwave Radiation Atmospheric CO2 Shortwave Radiation Temperature Respiration Boundary Layer Conductance Sensible Heat Photosynthesis Global Ocean and Atmosphere - Climate Scale Transpi-ration Stomatal Conductance Cloud Formation Instability Biomass Shoot Growth Atmospheric Moisture Evapo-ration Root Water Uptake Albedo Root Growth Precipitation Soil Moisture Streamflow River CO2 Soil Carbon

40. Basic Characteristics of Water Cycle • Natural systems associated with the water cycle are under continual evolution. • Water is both a “driver” (through hydrologic variability) and a “medium” of interaction for a variety of natural processes. • The two roles are fundamentally different. • Water cycle consists of a network of cycles that interact with each other, that is, the water cycle is a hypercycle. • The interaction between these cycles provides a mechanism for the dynamic stability of the water and energy cycle in the presence of positive and negative feedback cycles.

41. Energy Cycle Water Cycle On the Role of Hydrologic Variability • “Hydrologic variability” plays a role as important as the variability of energy in driving all global systems • This independent (but linked) role suggests that global systems (ecological, biogeochemical, …) are as vulnerable to the anthropogenic changes in the water cycle as they are to the changes in the energy cycle Sustainability and Environment

42. Conclusions Climate and ecology interact to define atmospheric pathways that are at the heart of hydrologic variability. Vegetation should be seen as an adaptively and actively modifing the water cycle. Water is both a driver and a medium of interaction for open dissipative systems – water cycle is A hypercycle.